Gamecube----Geared more toward children, but games trickle out for it. Not many new releases very often. Maybe 3 good games a year. Cannot be used as a DVD player.
PS2----Getting ready to be replaced by PS3. Tons and tons of games to choose from since it's backwards compatible with the PS1 games. Also makes picking up a "new" game very cheap. Another advantage is that it's a DVD player as well. Not a great one, but not bad for kids.
XBox---By far and away the best system on the market. Plenty of games, great graphics, everything you could want. It does cost $30 for the remote and transmitter to make it a DVD player, but it's a better DVD player than the PS2. Also, it won't be replaced anytime soon. Just like PS2, tons of games under $20.
I am the Reaper of Men,
The Chaser of Souls,
The Weaver of Nightmares,
I am The Heart of Darkness.
I now, and ever will be,
The Purity of Evil.