There have been a variety of improvements and enhancements to Windows 7 since Microsoft's latest operating system went final and made it's appearance on store shelves.
Not all of them are obvious. Factually, many are not in Windows Update.
Contrary to early speculation that 'XP mode' would be available to all in 'Service Pack 1', it arrived about 5 weeks ago as 3 separate downloads.
Be sure to check the system resources but you don't need hardware support or a special CPU anymore.
It's available in 3 download steps and works great using virtualization to deliver a Windows XP desktop when needed or desired. More information can be found here.
Not actually part of Windows 7 but marketed heavily to users, the Windows Live suite of programs (Windows Live Mail, Windows Movie Maker, Family Safety, etc .... ) has gone through numerous upgrades. Some of them are significant. One even effected a Microsoft Webcam I had.
The only way you'll see these improvements is to freshly download the suite or portions of it here. The installer recognizes the libraries etc., that need to be updated, asks first ... then overwrites them.
Most obvious to me, but maybe not to some, were the occasional updates being delivered automatically (but separately) to the Windows Media Center.
Opening the Media Center this evening I not only noticed new features and new content but a freshened menu that now plays the current program translucently behind the menu (IE: You can channel surf with the video running in the same window background .... pretty neat :).
HD channels delivered full screen video on my laptop excellently (on a local 5 GB Internet connection) with no problem at all. I haven't visited Media Center frequently enough, but that seems to be an improvement in buffering.
With Netflix, CBS, Rev 3 (Tekzilla) and more on-board (NCIS anyone?? :) .... a few more content deals and there's no doubt the PC version of Media Center could be (or already is) a viable competitor to iTunes (in some ways) and / or the recently enhanced Hulu.
If you haven't opened Windows Media Center recently, give it a try.
Overall, there's no doubt that if you're running a licensed copy of Windows 7, the improvements continue rolling out ...... whether it's compatibility, productivity or entertainment.