How so?

PS2 - loads of games, lots of RPGs

PS2, that is the only possible answer. Nearly all the games, the best ports, the best controller (for me). I'm still playing it occasionally, mostly J and D at the moment

I played PS2 the most the Dreamcast second

In order of my preference:

PS2
GameCube
Dreamcast
Xbox

My heart says Gamecube, but my head says PS2. There were droughts, but when the Cube was good, it was REALLY REALLY GOOD. When the PS2 was bad, it was still good (not counting that horrid first year). PS2 takes it.

ps2 hands down.. because of variety..

here is my order:

ps2
gamecube
dreamcast
xbox

I loved my Xbox but PS2 is the obvious answer. The only thing the PS2 doesn't have are Nintendo's flagship titles or the Halo series. I loved Halo and Nintendo's games are always stellar but the PS2 had such an immense library and had AAA titles in every genre not to mention getting exclusives of its own like the original GH/the Ratchet series/GTA time exclusivity/MGS/God of War.

Depends upon criteria.

Overall it has to be PS2 I think. It had broadest catalogue of games, so the console really did offer something for everyone. It has kids games, adult games, sport games, RPG, etc.

Gamecube was really nice but a little to one note for me. Xbox at that time for me represented a cheap PC for those that couldn't afford a decent PC - also I'll never forgive the console its part in ruining Dues Ex 2 and adversely affecting Thief 3.

Dreamcast never really got the chance to make an impression (at least from my point of view).

I guess in terms of simple metrics such as sales of console, dominance of brand, sales of games, etc. the PS2 obviously dwarfed everything else.

Probably worth noting however that last gen pretty much all my gaming was on PC as I bought the PS2 for my kids - although I did play ICO and SOTC (two of the best games ever) and Silent Hill 2, 3 & 4 on it (oh, and Farenheit or whatever it was called - interesting if flawed experiment and I'm curious what its development team do with heavy rain: hopefully they won't cover the actual game with large flashing button cues this time!).