So...my local game shop, which I consider to follow in the same spirit of GOG (i.e., making old console games and consoles available to those of archaic taste) had a sale and I picked up a Gamecube, all the prerequisite peripherals, and a copy of Metroid Prime for twenty five bucks. I've already found the rare Legend of Zelda heritage collection (LOZ, LOZ2, LOZ:OOT, and LOZ:MM), Paper Mario, Pikmin, and Metroid Prime Echoes to go with it. Now I'm wondering...anyone else have any recommendations? This place can get me pretty much anything I want if I'm patient enough, I've just always been a fan of the PS2, Metroid, and Zelda (the latter two of which I first played on the GBA). I basically made this first shopping list by browsing IGN's top 25 Gamecube games and dredging up memories of playing Ocarina of Time for the N64 - I know very little about the Nintendo franchises other than this.
Oh, and Metroid Prime is possibly one of the absolute best first person shooter / atmospheric suspense / space marine games I've ever played. Umm...not that there are THAT many that fit in that category...
So anyway...I just wanted to share my excitement, but I suppose I can make this a question - are there any CONSOLE SPECIFIC Gamecube games that I just shouldn't pass up? Thanks in advance!

Borderlands as well had a solid engine but a unique look. I think Cell shading may be the way to go to keep the humor of the series while still making it a serious shooter. If Crytek are serious and EA show the money they could have a serious competitor to TF2. No game could ever top the modes TS had especially Monkey Assistant.

About Timesplitters 4:
"As of 17 August 2009, the project has officially been declared as on hold. In a recent interview, Crytek UK claimed that they would continue the project once there is a high industry demand for such a game"

Is there anything else are you looking for in the way of games? Is there a favorite style you have? If you want further information on any game, I am sure myself or others here will be able to give greater detail.
Also, you are correct about Metroid Prime it is a remarkable game and every game should learn from it where the loading screen from area to area is as if you are still in the game riding the elevator. No silly black screen with a loading bar!

This is the only thing I dislike about my GameCube. The only way to get the best image quality without it is to play your GameCube games on a Wii. Other than this, I have nothing bad to say about the GameCube experience.

There is no Star Ocean games on the Gamecube.
Anyway, it looks like everything I'd recommend has already been mentioned.
Baten Kaitos: Eternal Wings and the Lost Ocean
Baten Kaitos Origins
Star Fox Adventures
Cubivore
Tales of Symphonia
Super Mario Sunshine
Any other games I'd add are either Dreamcast ports or multiplatform and you said console specific.

+1
Path of Radiance is one of the best Fire Emblem games and its sequel is even better.
Other good games I haven't seen being mentioned are:
Star Wars Rogue Squadron II: Rogue Leader (its sequel isn't as good)
Puyo Pop Fever
Capcom vs SNK 2
Pikmin

Problem being the sequel is Wii exclusive, not GCN.

I never said it was for GCN, I just emphasized that both games were good and stated my support for Path of Radiance ("+1"). I start my recommendations for GCN games in my second sentence.

LoZ Wind Waker. After that LoZ Twilight Princess. WW is just so much better even though TP is more compact game.
Eternal Darkness Sanity's Requiem is probably the best GC game that I have on my shelf.

Here's what's in my collection. I can't say that I have any regrets. I bought a lot of quality titles:
http://backloggery.com/games.php?user=jt&console=GCN

When you consider that the Wii just works with GameCube games (if you already have the controllers and memory cards, and are prepared to give up any networking features or the GBA Player), Nintendo could teach Microsoft and Sony a thing or two about backwards compatability.
I realise that it's not perfect, but it's a hell of a lot better than the 360's (certain games only, requires download) and the PS3's (excluding the first versions, PS1 games only) efforts.

Uh...I had two pokemon I had trained...the little Sableye goblin thing and a killer fire chicken. I was working on a couple more, though...

Yep, I was wondering how they managed to do Metroid Prime with no load times until I happened to try to 'skip' through the 'cutscene' of Samus in the elevator, heh.
And let's see, you're absolutely right, I was remiss not mentioning this...
My favorite games are almost exclusively action-adventure platformers or CRPG's (Rogue Galaxy, Dark Cloud 2, Vexx, OOT, ULtimate Spider-man, and The Force Unleashed). I do like RPG's on occasion, but I'm afraid I'm terrible on follow-through - if I don't beat a game in a week or so, I'm liable to get bored and wander off to find something else to play.

To be entirely fair, it's easy when you're essentially using the same chip as your last gen. The 360 and PS3 have to emulate their titles to a far greater degree. (With exception to first PS3s which actually have PS2 hardware.)
I just wish that Nintendo didn't have that special chip on the end of the GameCube component cable. Seems like that's what has stopped people from doing their party versions. In any case, I have no interest in paying all that money for a Wii. I'm not knocking the thing, but to be honest it has no games that interest me enough to justify the cost of a new system.

Harvest Moon series and Animal Crossing.