Hehehe...alrighty - well as you've got Windows Vista, you may require a bit better video card and more
ram then what you already have (i'm assuming you've got at least 1gb of memory).
To be honest however, almost all games will run nice on that computer, just not on max detail.
If you like RTS, I'd recommend the Dawn of War series, as that will run really nice on your computer. Same with Warcraft 3.
If you like FPS, pretty much any game based on the Half-Life 2 (Steam) engine will play nicely
Sports games aren't generally hardware hungry, so all these from EA should work fine.
If you want specific recommendations to games, check out the
What Games? thread and see what games are being played, and find out what ones you think you'd like (google always has the answer

)