You can't have a modern computing platform without an online store, so it's no surprise that Xbox One, like its predecessor, ships with an on-console Xbox Store. But Xbox One's Store experience is a bit difference than that of the Xbox 360, and there are some mostly positive differences.
The single biggest change with the Xbox One has nothing to do with technology: Now, you can purchase any Xbox One game title online, in electronic form. With the Xbox 360, there was a waiting period before new, AAA game titles were made available that way.
(There are some differences in the way downloaded games and retail, disc-based games work, but that's another story. Check out Xbox One: Game Downloads for the gruesome details.)
You can access the Xbox Store through the dedicated Store app, or by saying "Xbox, Store" at any time.
(You can always reach this top-level menu by tapping (B), repeatedly if necessary, on the controller. This was an issue with the initial release of Xbox One, since fixed.)
You can also navigate to the Store group in the Dashboard, which features large tiles for Games, Movies & TV, Music and Apps, each of which provides a direct inroad to that part of the Store.
Each of the main areas of the Store is presented as a panoramic experience. The Games Store example, has groups like Featured, Search/Use a Code, New Releases, Add-ons, Top Games Right Now, Popular Games, Recommended for You, New Game Demos, Top Selling, and Top Rated, which extend horizontally past the screen you're view.
Individual content—like a game—is presented with a landing page that is also a panoramic experience, with its own groups for screenshots, game clips, add-ons and more.
(Speaking pedantically, the Games and Apps stores are part of the Store app, whereas TV & Movies is part of Xbox Video and Music is part of Xbox Music; but you can navigate back and forth between each easily enough.)
You can also use Bing Search to find apps, games, music and videos, and if you're so inclined it's easy enough to launch this search using the Kinect voice control, "Xbox, Bing" followed by whatever search term you wish. A search for "Boston" comes up with the following, and as you might expect that first large tile launches that artist's page on Xbox Music. But keep scrolling over to the right, and you'll see results for TV shows and movies (in this case) too.
A similar search for Rome also includes game results.
It's worth mentioning that other services can link into the Store too. That "Rome" search also triggered music, TV show, and movies results, the HBO series "Rome" being one of them. When you visit the landing page for that series, you can choose between Xbox Video and Vudu for purchasing. The movie "To Rome with Love" is available on Xbox Video, Redbox Instant and Vudu.
Xbox Store isn't perfect. The Xbox One games selection is still pretty weak this close to launch, and it's not possible to buy music or add it to your collection from the console for some reason. (You can, however, pin music, as you could with Xbox 360.) And I have questions about the viability of this simple UI once a wellspring of games finally is available. But overall, it's a solid effort and one-stop-shop that will keep couch potatoes where they belong: On the couch.