I owned a Cube, Xbox, and PS2. I sold the Xbox and I don't have any games for the Cube (because I bought it over a year ago for Zelda: Twilight Princess...
My favorite games of the generation (ordered by console, not preference):
Super Smash Bros. Melee
Phantasy Star Online Ep 1&2
Resident Evil 4
Halo
Fable
Suikoden III
Suikoden V
Devil May Cry
Metal Gear Solid: 2
Metal Gear Solid: 3
Games I'm still waiting for:
Zelda: TP
Valkyrie Profile 2
Okami
Game of the generation goes to Resident Evil 4, but I don't feel it was enough to save the GC. Halo was great, but one doesn't need to own an Xbox to play it, if you know what I mean.
Oh yeah, and I bought Fable: LC for PC. It has glitches (non-legible text), but it's got some improvements as well. I have no reason to own Xbox.
The PS2 played DVDs, my old Playstation games (which I value more than my PS2 games), and a decent handful of PS2 games. That's what it took to stay in my room, whether it got played often or not.