Get whichever one has games you want to play.
I would just get a PS2, enjoy it's dirt cheap games, and then get an XBox360 when it pricedrops or when you get an HDTV. Then enjoy it's dirt cheap games.
EDIT: Looking at your game collection, I see that you don't list any Gamecube games. If you don't have any, there's a lot of great Gamecube games to look into as well. And it'll be cheaper than getting a whole new console.







