XBox is nice since you don't have to buy any extra memory cards and it's cheaper than the PS2. There aren't as many games, but they've gotten alot more lately so perhaps they will continue to increase the selection. PS2 is nice since you can play DVDs with no additional cost, but you gotta buy the memory card. It's also $179 but has more games. I went with the PS2 and so far love it.
EB Games near me sells used XBox's for $89 and used Gamecubes for $39.