For just friendly things it's the nintendo gamecube because it has the best games for multiplayer like Soul Calibur 2, SSBM, Mario Kart DD, Mario Party 4 or 5, ect.
The xbox system is based more on one player games if you ask me. The games that are multiplayer are meant to go online so it wouldn't be a "party system."
gamecube is the best party system.
Halo 2 lan parties are fun, but their a pain to pull together. I've only had 2. and only 1 had 16 people. it's just to hard to have 4 tvs and the router needed.
Mario party,
double dash is a AWSOME lan party game. TO bad you have to use the almost NOn existant modem/lan connector doo-hicky to conect them. I've only done it once at a lan party organised at my school. it was so fun. it's just chaotic. I love the team work needed. I'm great being shotgun. I know how to help use the side attacks to make sharper turns, get items, and comphensate for things.
metroid is a fun party game for what it's worth.
and donkey konga is a riot. SLAM SLAM SLAM CLAP CLAP CLAP