Here are some games I love to play, most are older than 2008, so you'll most likely have to use compatibility mode, some you won't.
OMF:2097: This game is quite old, made in 1997 or so, you'll need DOSBox to make this run, and DOSBox will run fine on Windows 7. This game you basically play as 60+foot tall robot, and fight other robots. It's 2D like the old Duke Nukem games.
Oblivion: Came out in 2006, not sure if this one works on W7 or not. I don't have the game anymore, so I wouldn't know, but it's a lot like Fallout 3, except I think it's better than Fallout 3. It's also like Gothic 3.
Warhammer 40k, Dawn of War: Another old, awesome game that came out about 2004 or so. It has very good graphics for a game it's age. Not sure if this one works for W7, haven't been able to test it yet.
Diablo 2: Another oldie, but a good game. Haven't played it recently, myself.
Battlefield 2: One of my favorites. This game is pretty fun online, especially if you have mods installed on it. Works fine on Windows 7 for me.
Homeworld 2: This one came out in about 2003, it's an RTS space fighting game where you build spaceships and what not. It's all space fighting, no "ground battles".
Star Wars: Empire At War, and it's expansion Forces of Corruption: This is another favorite of mine. It was released in 2006 or so, and has a crapload of mods out for it. You can build armies of ground troops, or space ships, and play either ground battles or space battles.
Unreal Tournament 2004: One of my favorites. If you've ever played the original Unreal Tournament back in 1999 or so, this one's very similar, except it has better graphics and what not.
18 Wheels of Steel Haulin': If you're into "truck driving" games where you drive a diesel trucks and deliver trailer loads (and get paid for it), this one's for you. There are several games to this series. Use Google if you want more info.
Freight Tycoon: This one's similar to Monopoly Tycoon, except you own your own company, and you buy trucks/trailers to have these trucks deliver stuff for you, except you're not driving the trucks. You just assign them "contracts" that make you money if you deliver the goods on time. No idea if this works for Windows 7 yet.
Morrowind: Same as Oblivion, except it's older, and doesn't have great graphics as Oblivion does, but it's fun anyway. No idea if this works with Windows 7.
That's all I can think of right now.