PS2, X-Box, or GC ???
Just as in the last post, first determine the kind of games you like and wanna play (racing, fighting, action/adventure, sports etc). There's no point getting the most powerful system if the games don't interest you.
That being said, I would lean towards a PS2 or an X-Box. The PS2 is less powerful, but it can play DVD's right out of the box, unlike X-Box, where you need a seperate adaptor for that. Also the newer PS2's come with the network adaptor built in. X-Box does have better graphics and a HD advantage.
Most of the games that appear on X-Box will appear on PS2, and vice versa, with the exception of a few exclusives like Halo, GTA, and Metal Gear Solid. If any of these exclusives is the deciding factor, than go with that system.
My Favourite: The PS2.