The SOCOM series. If people didn't figure out how to make mod disks, it would have been the perfect game in my opinion. The new gameplay videos for SOCOM Confrontation are pretty amazing too. Too bad I have an Xbox 360...
Also, the Call of Duty games made by Infinity Ward are phenomenal. Treyarch's CoD games are hit or miss, but FPS fans will still like them.
The console Battlefield games are also some of the best. BF2:MC's campaign was pretty cool because of hotswapping. Bad Company's campaign is really mundane, but the explosions and the sound are nice.
Burnout Paradise was also well-worth the money. Just hope you don't take down a pervert with an eyetoy or an Xbox LIVEvision camera.
America's Army for the PC takes low system requirements but it can look nice if you've got a good graphics card, has decent gameplay, and it's FREE. If you're broke, play it.
F-Zero X and F-Zero GX were great too. GX's story mode is ridiculously hard. Just try to outrun Goroh.