While by no means am i dismissing xbox's awesome lineup of 2004, Johnny you seem to be forgetting quite a few factors for gamecube.
Lets start with pokemon colosseum shall we? The first ever home console pokemon thats an RPG.
Then we have RPGs, a genre that is rather untapped on gamecube, starting with tales of symphonia and baten kaitos, along with an imminent announcement of VFQuest. Then we have Zelda next which will be unveilled at E3 2k4. I can already hear a few peoples coming here and say "but zelda WW didnt move that much harware!", but the thing is that zelda next wont be using the same rendering technology as WW if rumors are true (im pretty sure EAD realized that cel shading didnt attract as much as they thought). Then we have Resident evil 4, which is said will be a major shift from the main series, maybe enough to attract gamers once more. Metal gear solid and final fantasy.. remakes or not, they have shiny bright names in the eyes of mainstream gamers. What else? Oh, the sequel of the best Gamecube games and arguably one of the best this generation, Metroid prime 2. If the first MP is anything to go by on retro's first effort, i think we're in for a treat. Donkey kong adventure, rumored to be 2.5D, but a donkey kong platformer will attract gamers thats for sure. Even the shitty 64 incarnation sold really well.
There's also uncertain games that are too far off to tell if it will be good or able to move hardware, but killer7, geist, PSOIII, Mario tennis, pikmin 2, star fox 2 (im confident in ace combat team), donkey konga (music games arent for me but who knows how it will catch with families or party freaks).
Thats only stuffs that we know of course. But i wouldnt dismiss gamecube quite yet, i think they'll reinforce their worldwide 2nd position even farther in 2004. Heck, depending on how pokemon is received, that franchise alone could counter halo 2 + ninja gaiden + RC2 sales combined, its an IF but i wouldnt be surprised with pokemon.
And if you're reading this and think that im heavily biased toward gamecube, well thats because you have short memory, i'll re-quote what i said in the first sentences
by no means am i dismissing xbox's awesome lineup of 2004
There good. I'll say this, as an owner of ps2, xbox and gamecube, 2004 will ruin me and probably kill my social life