It depends on the games you want to play.

I would steer clear of integrated/onboard video for high end gaming (newer FPS and MMORPG games) . I would also recommend 2 GB memory. My wife and I both play games and I'll list our specs and the differences I've noticed.

Her PC:
Athlon 2500+
1GB memory
Radeon 9700 Pro 128MB video

My PC:
Pentium 4 3.2ghz
2GB memory
ATI X800XT 256MB video

World of Warcraft
Me - Played flawlessly at highest graphic settings looked wonderful.
Her - Was able to play without problems, but only at lower graphic settings. This game forced the upgrade to 1GB on her PC due to extremely long zone load times and lag during multiple spell effects, etc.

Counter-Strike
Both - Plays fine on both systems. My system handles smoke, etc. far better.

Counter-Strike:Source
Me - Plays fine.
Her - Playable, but only at low settings.

Some games like Age of Empires, Warcraft, Starcraft, Warhammer, etc. play fine on both systems. Just depends on the types of games you plan on playing. After playing FPS games on my new PC I could never play them again on her PC (my old one).