Microsoft's Windows 7 pre-order is up, and in addition to Amazon, there are a number of retailers offering Home Premium and Professional at significant discounts:

Costco

Sam's Club

Best Buy

Walmart.com

Microsoft Store - Here, you can choose between packaged and download versions, by the way

Fry's Electronics

Amazon.com

Office Depot

TigerDirect.com

Office Max

NewEgg.com

Quill