The top third-party games, services, and international versions of games have been tested in Windows 7, so you should not worry about Windows 7 breaking your games. Feel free to move to Windows 7 because whatever you're playing now should work fabulously in Windows 7.
You can use Start -> Search to find any game you just downloaded or installed. No need to launch a separate application. Likewise, you won't need to launch a game to get more info about it: The Windows 7 Games Explorer can show you in-game statistics within a preview pane plus delivers up-to-date info about your favorite game publishers and gives you the opportunity to try new games.
The new Games Explorer will notify you whenever updates are available for your games so you don't have to go searching for them yourself or have to launch the game to see if there's an update waiting.
DirectX 11 support
DirectX 11 means better games, pure and simple, with more advanced features for games to use.
An increasing number of gamers are using multi touch devices. Windows 7 supports multitouch-capable machines, so you can buy the latest and greatest multitouch laptop or desktop confident it's going to work in Windows 7.
Here's a bonus reason for you: Windows 7 is going to bring back Internet Backgammon, Internet Spades, and Internet Checkers because you can't spend all your time hardcore.