I think this thread could be quite fun, please respect others opinions in this thread because even though you can back up your opinions with fact, it is totally opinion based.

Right the 4 contenders are the Dreamcast, Gamecube, PS2, XBOX

Each console had its own good qualities.

In my opinion it was the gamecube, I thought they quality of games suited me better. I never owned a dreamcast, so I can't comment on that one.

However each console had dozens of good games.

Info for each console can be found on these sites...

PS2 - http://en.wikipedia.org/wiki/PS2

GC - http://en.wikipedia.org/wiki/Gamecube

DC - http://en.wikipedia.org/wiki/Dreamcast

Xbox - http://en.wikipedia.org/wiki/Xbox

Playstation 2, because it has the most variaty in games, and also had the best games of last genration.

Gamecube is secound, because it had mario, xbox only had halo and ninja gaiden. Therfore ps2 is the clear winner last gen in terms of games.

For sheer diversity, the obvious answer is the PS2. However, I find myself liking the Xbox's catalog more and more. Not only does it have a ton of quality PC ports (which basically means I can get by without a gaming PC), it also has the best versions of all last-gen cross-platform titles (most such titles look downright ugly on the PS2 in comparison), and a good number of exclusives in its own right.

The only catch is that most of its library is limited to Western games, but I'm not much for quirky OMG KAWAII ^___^ Japanese stuff anyway (except for Katamari).

PS2....but damn the gamecube had animal crossing...xbox had halo......god...good times

Multiple factor decided that for me

1.- Reliable hardware
2.- I loved the GC's controller and hated the Dual Shock as you should already know
3.- I have never been the kind of person that buys crapload of games. I usually buy ten games at max per year, so PS2's huge library was not a factor for me
4.- I'm a Nintendo fanboy, so Nintendo franchises are a huge plus for me
5.- Quality over quantity
6.- I don't like GTA
7.- I only owned the Gamecube

So, Gamecube for me.

ps2. any other answer is a lie ;)

i think the ps2 just beats the gc in my opinion(i never owned xbox and dc)

Gamecube;

Why?... It had Eternal Darkness and was the original console for Resident evil 4... And i love Nintendo games!

I.m.o Gamecube had the best controller too! And better graphics then the PS2, which is a fact!

EDIT: Only disadvantage was the lack of online games. 

Mind you after saying gamecube, I just looked over at my TV and my xbox is the only last gen console still set up. I wonder if it means that the xbox had longevity edge for me. however I just play my GC on wii and PS2 on Ps3. but I still play a lot of XBOX games

That's only because you don't have a 360.