Have a Gamecube, and never felt I was missing anything. I'm one of those notorious first party addicts - give me Mario, Zelda, Mario Kart, and then I'll have a look at the other games.

There was a period in the Gamecube's life (I think it was 2002-2003) when the system seemed like the place to be. Good games were hitting shelves so fast, I couldn't keep up. Still, I think that by 2004, anyone that was a serious "Buy more than 1 game a month" gamer was secretly envious if they didn't own a PS2 or XBOX.

I didn't felt I miss any game with these five (Super Mario Sunshine, Mario Kart DD, Mario Party 4, METROID PRIME best game i've played and Metroid Prime 2 Echoes)
Gamecube gave me more than 5 years of fun and wii will double that fun, SHURE.
And Metroid Prime ahh these good days, this game taught me the true significate of videogames (thanks retro)

Conclusion: one thing missing... nothing.

All I had was a GameCube, and It was fine by me. I don't care much for games on the other systems, and If I did, it thankfully hit the PC as well. So, I didn't miss anything.

nope not at all glad I didn't buy the other 2 untill they were cheap, frankly all the "great games" they offerred were anything but and I would say range from medicore at best to terrible,
with only shadown of the clossus, the silent hills, and killzone actually proving to live up to the expectations, and to a lesser extent Ico
halo, blech uninteresting fps
fable, ninja gaiden, god of war, all should be called beat
em ups or hack n' slash games cause frankly they're about as good as capcom's old knights of the valor games, but one player
the metal gear games are just clunky action games that because people go retard over their story they are anything, I prefer games that have characters that got past their teenage angst.
don't care about final fantasy's or sim racing games so they're both out immediately
still haven't tried okami and a handful of other games, but I won't judge them untill I've tried them
seriously I'd say the xbox is by far the worst successful system in terms of the game library ever.
most of the other big

I owned only a GameCube. My sister owned a PlayStation 2. Any games I got I just used on her system.

I had Cube-only for quite a while, until I could fanangle a way to get PS2 for less than $100 out of pocket (this happened when PS2 hit $199 retail).  I wanted a PS2 for a few games, but I never really felt like I was missing out on a lot.  Honestly, I had the money and could have bought one if I did feel that way.  The first games I got for PS2 when I got it were Adventures of Cookie & Cream (still the best PS2 game out there if you ask me) and Star Wars: Starfighter.  There are plenty of good PS2 games (it's a much better system than PS1 in that regard), but honestly there are no "must-haves" for me at all, even to this day.  Cube still has SSBM in that category.

I had been out of console gaming ever since the SNES came out, and only got back to it when I happened by chance to play Super Smash Bros. Melee in nov/dec 2005. I was instantly addicted, quickly acquired a used Cube for dirt cheap, and proceeded to spend 2006 playing all the dirt cheap, but excellent, Cube games I had missed during my long period as a PC gamer. Never felt left out during the time, as there were more than enough GC games to keep me busy for the time being.

I ended up getting a Wii for Yule 06, and finally a used Xbox during the spring, so I guess that broke my Nintendo exclusivity. My gaming purchases are pretty random and opportunistic, as they mostly occur when I see something I want for cheap enough. =P

Fully intend to get a PS2 eventually, but second hand ones are still almost retail priced (100€+) around here, and I managed to play most of the games I was interested in by doing 1-2 week console exchanges with a few friends anyway. Probably borrowing my Wii to a friend after I've had enough of MP3 and SMG, so I'll get to finish Okami.

I only owned a GC because that's how Nintendo dragged me back into gaming.
I had stopped playing altogether, and Nintendo lured me back with the title screen of Zelda Wind Waker.
So of course I've missed some RPG, but it will be corrected soon enough.

I was a stupid little kid that was in love with nintendo.