I was a lapsed gamer last generation, occasionally playing PC games as well as my sister's GameCube.  I think the heart of the question can be summed up as: "Do you you feel that you are missing out on the games for the system(s) that you don't have?"  My answer, regardless of which systems I may own at any one time, is an emphatic "yes."  There are many great games out there for consoles, past and present, that I don't have--and yes, I feel like I am missing out.

But here's the thing: I also feel like I am missing out on games for the Wii and the 360, which I do have.  There are so many good games that are either currently out or in development, that I know I will not be able to play them all.  I accept that.

For a great deal people, money and gaming time are finite, and thus we have to make choices as to which games and consoles we purchase.  As I stated in your "Wii owners" thread, GranTurismo, I don't own a PS3 because it does not offer me enough games (that I would personally like to play) for the price.  Would I like to have one if I had unlimited money?  Absolutely.  There are a number of games for it that I would like to try.  I remember complaining to my brother, a little while ago, about how I wouldn't get to play Uncharted.

As someone who works 8 to 5, and has a slew of other commitments, I won't be able to play every single fun game for the systems that I do have, let alone the awesome games for the systems that I don't.  I actually had to make a list, prioritizing which games to purchase, for which systems, and in which order.  You know, sometimes I feel like shouting to game devs the world over "Quit making so many good games, I ain't got time to play them all!"  But that's just silly, I realize.  I honestly appreciated the games drought in the months prior, as it allowed me to catch up on my games library backlog.  Heck, I only recently finished Um Jammer Lammy for the PS1!

I wish I had more free time, but I don't.  I wish my paycheck were significantly larger, but it isn't.  You know, it's true: life is too damn short.  All we can do is enjoy the hell out of the games that we are fortunate enough to play.

I bought the Gamecube instead of the Dreamcast, Playstation 2, and Xbox, at the beginning, and I still think it's the best console out of the four. I had the Gamecube for many, many years, until one day, I bought the Dreamcast, Playstation 2, and the Xbox, all within a few weeks, just to see if I was missing out on anything, from the many years before. Honestly, I could have lived without the Dreamcast, Playstation 2, and Xbox. In fact, the Dreamcast, Playstation 2, and Xbox, are all getting dusty in the closet right now, and the Gamecube is still being played. Actually, no, the Gamecube is in the closet too, for I play the Gamecube games on my Wii not.

Notable Gamecube games:

Super Mario Sunshine: First game I owned on the Gamecube. I still think it is the greatest Mario game ever created. The graphics were amazing at the time. Super Mario Sunshine owned. I mean, over 91% in Game Rankings, how could you complain?

Super Smash Bros. Melee: The greatest fighting game of all time! Before I played Super Smash Bros. on the Nintendo 64, I never really liked fighting games. To me, they just existed in mediocrity. Sure, I played them, but I always accepted them as okay games, and they all felt the same to me. When Super Smash Bros. came out on the Nintendo 64, I thought it was just awesome. When Super Smash Bros. Melee came out, I liked it even better. Even today, I wont touch another fighting game.

Mario Kart: Double Dash!!: This game owns! It's fun, and addictive. One of the greatest racing games... Ever! How can you not like Mario Kart?

Those were the three games I played... And played... And played... Maybe even a little too much. Around the time when I bought the other three consoles, I bought more games for the Gamecube, which personally, never enjoyed as much as the three mentioned above, but still liked them.

Even though I liked the Gamecube the most, I still liked the other consoles.

Notable Dreamcast games:

Sonic Adventure: One of the greatest Sonic games ever created! OVer 87% in GameRankings, Sonic Adventure beats every other Sonic game after it, and a few, before it. Sonic Adventure is a dream.

Sonic Adventure 2: A great successor to a master piece. Sonic Adventure 2 was over the world.

Well... That's all folks!

Notable Playstation 2 games:

Jak and Daxter: A good platformer. Enough said.

Ratchet and Clank: A good platformer. Enough said.

Rayman 2: A good platformer. Enough said.

Klonoa 2: A good platformer. Enough said.

Well, being a platformer fan, I definitely found quite a few good games on the Playstation 2. Still though, I just didn't enjoy it as much as the Gamecube, but I still enjoyed it.

Notable Xbox games:

Halo: Awesome shooter.

Halo 2: Spectacular shooter.

Well, that's all folks! The Xbox is definitely my least favorite out of the four, but I still like the Xbox. I just like the other consoles more.

I own almost every single gaming machine in the world, and I must say, out of all of them, the Gamecube is probably somewhere in the top 5 list.

I bought a Gamecube mainly because I love Nintendo games, natch. Sunshine, Melee, all the rest -- had to have them. And there were many other good games on it too, especially REmake and Eternal Darkness. (RE4, which hit later in its life, goes without saying.)

I might have bought a PS2, but in the last generation I was less into console gaming then I was previously or am now. For instance, I told myself, "I'll probably get the PS2 after FFX comes out." That time came and went, but I didn't feel the need to go out and get a PS2. Ico was awesome -- didn't make me buy a PS2.

All the great games coming out for the PS2 weren't enough to make me buy it, because my gaming appetite was sated by the Gamecube and the great games I hadn't yet played on the PS1. Einhander, FF Tactics, Bushido Blade ... The PSone was my PS2, even though there had been a Playstation in my family, which I played all the time, since 1996.

Another reason why I didn't feel the need for another system is that I was playing a disgusting amount of StarCraft, and later Diablo II.  WarCraft III I played, but it never took over my life like those two games did.   

There were only 3 games that caught my eye on the Xbox: Halo, Panzer Dragoon Orta, and Oddworld: Munch's Oddysee. That was not enough to make me buy the system. However, my brother's wealthy friend loaned us his Xbox, and Halo, for about 3 months, so I had plenty of time to play the hell out of Halo. Then he took it back, and I hardly ever touched the Xbox again, except to get in on the occasional Halo multiplayer game -- and I didn't miss it.

I had a PS2 and sold it after I played FFX. Biggest mistake I ever made; (never got to play FFXII, Shadow of the Colosus etc). After 2 years I bought a GC with Pokemon (just love them critters). Just in time to play RE4, Fire Emblem, Zelda WW; to answer your question, I guess it was more fanboyism than anything that drove me the GC way (fanboyism for Pokemon, that is).

I swear, people go stupid over sales.  What was so great about the Xbox compared to the Gamecube? Some of the greatest games ever made graced the Gamecube, yet people refuse to give the system credit, since it "lost" to the xbox by a petty 2m units. I have no idea why fans get so stupid over console wars when it doesn't have anything to do with your console being fun or not.

I bought a Gamecube because it had the better library at the time. I also feel that it was the best console hardware wise, thus offered the best gaming experience. The Gamecube had no load times, the best controller, and some of the best graphics ever seen at the time. Also, the Gamecube was very cheap, and didn't have the same hardware problems the PS2 did. There really was no reason to buy the PS2 over the Gamecube. The PS2 was alot like the Wii; a over hyped, piece of shit compared to some of the systems. It was all hype at the time. It took the PS2 a long time to build it's legendary library.

The Xbox had a very one dimensional library, and was for select group of gamers. It was lacking in genre's that I really like, which is one of the main reasons I didn't buy it. Platformers, RPG's, and 2d fighters were a rare sight on the Xbox. There was no reason at all to buy an Xbox, especially with it's price tag.

^^ it always starts as the worthless hype-imbued machine but later all the gems come to it; It happened with the PS2, it will most likely happen to the Wii.

I only had a gc cause of:

-Metroid Prime! (IMO best game last gen)
-Zelda WW
-Friends already had PS2
-Edit: Xbox gamepad was the worst gamepad ever created under the sun

GranTurismo: Calling Zelda WW childish because of the cell shading look is just that. Childish. You obviously never played that great game and btw i was 26 when I played it ,and no i'm not infantile.

I only owned a Gamecube last generation and bought (and often traded in) over 70 games! I envied Ninja Gaiden on X-box really bad and Gran Turismo, Virtua Fighter and Metal Gear Solid 2 and 3 on PS2. Ironically my GC owning mate got a X-Box because of my love for Ninja Gaiden and he also bought a PS2 for MGS2 and 3 after playing MGS" Twin Snakes on Cube. He still didn't suddenly go selling his Cube or anything he just got the best of err 3 worlds!

I missed out but so did anyone who bought just a PS2 or X-BOX.

Resident Evil 4 should be missed for anyone who owned just an X-Box!

Metroid Prime 1+2 and Zelda: TP are unreal games that both PS2 owners and X-BOX owners missed too.

We all can't afford every system but Cube owners still got a great system for their money in my opinion!

I owned a GC all the way my friend had a PS2 we would swap when we wanted to play the must have titles, so i didnt miss out, eventually i picked up a ps2 when it became cheaper, just so i could "own" MGS2 & 3 (thats about the only must have titles on the PS2 i (personally) needed.

I only had a GameCube, and I don't regret it.
It was a dark age of surpression: everybody said''goddamn nintendo sucks it's for kids!'' and ''PS2 rulezzzz it has GTA!''.
It was up to us, Nintendo fans annex fanboys, to protect the name of the industry's Savior, and it's purple lunchbox console wich had more great games than sold units.

Now Nintendo has become the freaking Global Leader :D I quess my Nintendo exclusivity ends when I buy a 360 in December(Bioshock, Orange Box)