Best netbook operating system for older games?

I got an HP netbook with Windows 7 starter on it. I have a copy of Win XP laying around though. I plan on word processing, music/movies, and playing older games on it. Even old games sometimes perform like crud on it though. Would it be worth installing XP? What about the Linux based MeeGo? Any way to run PC games on that?

What about optimizing? Someone recommended Gameboost to help improve performance but I've read mixed reviews. What is the best way to optimise it? There are a few HP services running in the background but I don't know if they're even important.

-edited title.