Gamecube comes top for me as well; Resident Evil, Resident Evil 0, Resident Evil 4, F-Zero GX, Smash Bros Melee, Mario Kart: Double Dash and various others that I can't remember right now provided me with literally years of enjoyment.
Then it was the XBox; the advent of Live and PGR2 and Halo 2. Playing with the Poopgang lot on either game was terribly fun. Me, Craig, Thanny and Superking. Good times. Also enjoyed Halo 2 with the guys who used to post on Wakinglimb.
Next is PS2. Great games like Vice City and San Andreas among loads of others, but something never quite clicked with me for some reason. Can't deny that the good games were bloody incredible though.
Then Dreamcast. Nothing much to say about it really, I never owned it during it's initial run and have never had the chance to rectify my lack of experience with the console. Which is a damn shame. Sonic Adventure 2 and House of the Dead 2 were bloody brilliant on it though.