Heading into PDC 2008, where Microsoft finally unveiled Windows 7, the big excitement revolved around what exactly the software giant would deliver to testers. And yet, now that I know the answer to that question, it's a bit hard to describe. That's because there are two versions of the so-called milestone 3, or M3, build that Microsoft is showing off at PDC. There's the version we've gotten and the version they're demoing. And they're not exactly the same.

The more advanced version--the one we didn't get--includes three pretty major and attractive features (the enhanced Windows Taskbar, Jump Lists, and Windows Aero Desktop Enhancements)--all of which I'll still describe below. The version we did get looks a bit more like Windows Vista than what I'm calling the Microsoft version. And that's OK, of course, but it kinds of dulls the experience because the Microsoft version of M3 is pretty darned cool. I'm told we'll finally get all that extra stuff by Beta 1.

In any event, Windows 7 is all about the surface stuff, and in that sense it's a lot more like an Apple product than I'm comfortable admitting. But honestly, that's OK, because Microsoft already did all the hard work of rearchitecting the back end with Windows Vista. (And note that Apple's next OS X release, Snow Leopard, is dedicated to shoring up that product's back-end performance and reliability.) With Windows 7, Microsoft is refining the user experience and it's doing so with laser-like precision.

Let's dive right in. First up, the desktop.

Desktop enhancements

If there is a theme to the various UI-related enhancements Microsoft is making in Windows 7, it's "putting the user in control." In fact, that theme could be easily applied to many parts of Windows 7, including even User Account Control (UAC), which is being made more configurable and, if you'd like, less annoying. For now, however, let's focus on the UI specifically. Much of what's changing in Windows 7 is happening in the UI. And it's almost universally good news.

Enhanced Windows Taskbar

I've described Apple's Mac OS X Dock as a user interface disaster that messily combines shortcuts to running applications and other open windows with shortcuts to frequently-access programs that aren't necessarily running at the time. The Windows Start Menu and Taskbar, I felt, have always been far more logical.

Apparently, Microsoft agrees with Apple because the new version of the Windows Taskbar in Windows 7 dispenses with the separation of shortcuts for running and saved applications, and instead allows you to access either, willy-nilly, from the same place. That apparent mistake aside, the new Taskbar still has a number of important new features that separate it dramatically from previous Windows versions. It's really cool, and really, really useful.

From a visual standpoint, the new Taskbar is a bit taller by default than the one from Vista, and it's more glass-like than its predecessor with a clear sheen that lets the background seep through. As before, its broken down into a few logical areas, with a new Start Orb on the left, the shortcuts area in the middle, and the tray notification area to the right. To the right of the tray area is a small glass slab representing a new way to go directly to the desktop.

While the basics may seem unchanged, the details are all new. The Start Orb really lights up when you mouse over and click it, compared to Vista, giving more visible feedback that it's special. The Taskbar itself works more like the OS X Dock, again, offering shortcuts for both frequently-used and currently running applications and windows. And the tray is much more configurable and, thank you Microsoft, locked down by default.

For now, let's focus on that Taskbar, since all the big desktop changes emanate from there. In Windows Vista and all previous Windows versions dating back to 1995, the Taskbar did one thing and one thing only: It provided a place that was always available where icons representing running applications and open windows could be located and controlled. Over the years, it's been improved, but the basics have not really changed.

In Windows 7, the Taskbar is a different animal, and you might think of it as a combination of the Quick Launch toolbar and the classic Taskbar, where you can mix and match shortcuts for favorite applications, folders, and other file system objects with buttons representing running applications and open windows. All of these buttons--for lack of a better word--look identical. They're square glass buttons. Running apps and open windows are represented by buttons that have a visible border. Shortcuts for favorite apps and other objects have no borders. Like so:

Also new to Windows 7 is the ability to drag and drop Taskbar buttons in whatever order you prefer, a top customer request. You can also pin buttons so they're always exactly where you want them. As you mouse over buttons for running applications, nice glass previews of the underlying window appear, helping you more easily find what you want. Hover over that thumbnail and it goes full screen for an even better view.

If the button represents an application with multiple windows (or, in the case of IE 8, multiple tabs), the visible border is bigger, giving you a visual cue that something is different. And when you mouse over such a button, a series of thumbnails will appear, side by side, so you can access each of the application's windows or tabs. It's just nicely done

Improvements to the Taskbar don't stop there, however. If you click a Taskbar button, you'll see a new Jump List appear. Jump Lists supply lists of commonly-needed actions that are associated with the object you're clicking. (They also appear in the Start Menu. See below.) So even legacy applications that aren't Jump List-enabled will get a default list of actions. But Windows 7-savvy applications, like Windows Media Player 12, can populate their Jump Lists with application-specific functionality. In the case of WMP 12, you'll see options for Play All Music and Play/Pause, for example.

Notification Area lockdown

In a bid towards a tidier and less noisy desktop, the Windows 7 Notification Area has been significantly streamlined and locked down to prevent unwanted applications from interrupting you by default. Only four notification icons appear there in a stock Windows 7 install--Action Center, power, network, and volume--and when you install applications that add their own icons, those icons are hidden by default and their notifications are suppressed. Ah, bliss.

You can view hidden icons by clicking the Show Hidden Icons caret, but to allow a needed application access to your Notification Area, you'll need to right-click and choose Customize Notification Icons. Then, you'll be directed to the new Notification Area Icons control panel, which is a wonderful improvement over the dialog-based customizations previously available in Windows Vista and earlier versions.

You have a number of options for each icon in this UI: Show icon and notifications, Hide icon and notifications, and Show only notifications. Bravo, Microsoft, bravo.

Peek: A new Show Desktop

At the far right end of the Taskbar, beyond the system tray, is a new small glass panel that enables Peek. When you mouse over this panel, all of the open windows on top of the desktop because transparent so you can "peek" below them and view any gadgets, files, or shortcuts that are on the desktop. It's a handy feature, but I have concerns that people will inadvertently mouse over that area and be surprised when the entire screen changes so dramatically. We'll see: In the build we received, that panel just launches Show Desktop.

Improved Start Menu

While the new Taskbar is awesome, Microsoft already made dramatic changes to the Start Menu in Windows Vista, so the changes there in Windows 7 are less jarring. There are some important improvements, however. First, you can add some commonly-needed locations to the Start Menu--like Videos and Recorded TV Shows--for the first time. The Windows 7 Start Menu supports Jump Lists too. In this case, the list pops out into the right side of the Start Menu, which makes plenty of sense. And when you use Start Menu Search, the entire Start Menu pane is used to display search results instead of just the left side, as in Vista. Microsoft notes that the Start Menu is touch-friendly as well.

Aero Snaps

Moving to the desktop itself, you'll see a number of changes there as well. There's a cool new feature called Aero Snaps that lets you affect windows in interesting and useful way. For example, if you drag a window to the top of the screen, it will maximize. Drag it back down and it restores to the way it was. If you drag a window to the right or left edge of the screen, it will tile on that side and take up 50 percent of the screen width; again, dragging "off" the edge of the screen returns the window to normal.

Gadgets

The Sidebar from Windows Vista has been eliminated in Windows 7 because Microsoft feels that it took up too much valuable real estate, especially on laptops, which are a growing portion of the PC-using population. Now, Windows Gadgets appears directly on the desktop, and the aforementioned Peek feature will help users get to them quickly and easily. You open the Add Gadgets window now by right-clicking the desktop and choosing Gadgets from the pop-up menu. Otherwise, these objects work similarly to the way they did in Vista.

Styles

Windows 7 supports a customization feature called Styles (it's still called Themes in M3, but will be renamed). Styles are basically a combination of a background color or image, glass color, sound scheme, and screensaver, all packaged into a single file that you can share with others. Windows 7 ships with numerous built-in styles, of course, and you can edit these or make your own. There are even region-specific Styles, something Microsoft first implemented in Windows XP Starter Edition.

Windows Touch

Much has been made of Windows 7's multi-touch features and now that I've tried it on a demo machine, I have to say it's actually pretty impressive. (I'm still not sure I like the idea of touching a huge display regularly, however.) Windows 7 supports touch navigation, of course, with cool iPhone-like bouncing effects as window content limits are reached. It also supports touch gestures, so you can "flick" through folders, photo libraries, and the like. And it supports multi-touch, so you can pinch and expand to magnify and zoom out, twist your fingers to rotate, and right-click by holding down with one finger and tapping the screen with the other.

What's compelling about touch is that it works everywhere in Windows 7. It's not some hokey add-on that works only in certain applications and only partially in others. (I'm looking at you, Apple.)

Next up: Explorer and Networking