Off the top of my head, with quick off the top of my head ratings (note, a 5 is an average game on my scale)
Ones i'd reccomend
Smash Brothers - 9, nonstop fun, only dissapointments are the lack of a cheezy crossover story and lack of differing characters. There were enough characters but a bunch of them were just clones.
Eternal Darkness - 9 played through this game all three paths after i got it without touching another game. Only thing that held the game back was that unless you were incompetant you wern't going to ever be at low enough sanity to suffer the "Sanity Effects." Though it was fun after beating it all 3 times to go through and intentionally get a bunch of them. Had they made 0 sanity not lose health and make it so you lost sanity more easy including sometimes it being borderline mandatory and i think it would of been a perfect 10.
Fire Emblem - 7.5 Good SRPG, not my favorite fire emblem but fun, gotta love 20/20 Volke W/Occult Scroll.
Gladius - 8.5 Best SRPG on the Gamecube in my opinion. Was all sorts of fun, played through it twice myself and then a third time with my girlfriend maing use of the Co-op mode... which could have accomplished by just passing a controller back and forth but this way prevents "accidental moves". Good Story, lot of replay value with the different skills and classes.
Future Tactics - 6.5 Fun original Engine i would like to see more of, all sorts of awesome destructable scenary. Cons, the story sucked, well the story itself was ok for the kind of game it was, just a lot of the characters were annoying. Also the hidden upgrades were annoying as i know i'd often wait till the opponent was down to one enemy then avoid him while busting up scenary to make sure i didn't miss any upgrades.
Bust a Move 3000 7 - It's a bust a move game, if you like puzzle type games like this... then you'll like it. Good Party game in vs mode.
Custom Robo - 7 Customation is great, the story is fun because it's a big anime cliche story, the characters are a lot of fun all and all it's a great game. More team battles and a couple other types of battles like perhaps a free for all or two would of really boosted up my vote.
Mario Party 7 - 7.5 Not a lot of fun alone, but with 4 people it's all sorts of fun, i've actually seen someone get over a fight when they lost this game, it can get that competitive. Also great with Just your girlfriend vs a team of CPUS.
Megaman Network Transmission -??? - Got it from my friend when he said that nobody could beat the first level and that it was impossible. He lent it to me, i beat the first level was extremely surprised and gave it to me. Haven't played it much since then, but it seemed fun.
X-Men Legends - 5.5 - It's a really fun game, i'm just not an X-man fan, i'd suggest it to anybody who loves X-men games.
Lost Kingdoms 7.0 - It's a really innovative game as far as I can tell. Some review site compared it to pokemon... which I'm geussing they've never played the game because it's nothing like that. There is actually a challenge level involved since you get a limited number of attacks.
Super Monkey Ball 6.5 - I hate this game. It's the best gamecube party game out ther just for Monkey Target flying game. After i get this game i'd have 6-7 guys wanting to come over every night in the middle of the night to play this game and we'd take turns playing it. After I while I got seriously sick of it. The rest of the game modes were kinda mediocre. But monkey target is worth the price alone. Definitly worth it if you can get it for VC and XBL Arcade prices.
Others
MVP Baseball 2004 - 5.5 - Meh, I kinda wish i'd of got it on PS2 since my friends were more used to those controls. It's a decent game and all, but I mean really you can get a more recent game for like 5 dollars so why wouldn't you?
DBZ Budokai - 6??? - Fun game but others are out, my copy scratched too so i can't give it a full review.
Rogue Squadren 2 - 6 - It was ok, I liked the first one better however.
Madden 05 - 4 - The Theme song is an amazing song. Other then that, everytime i want to play a football game I head straight for Tecmo Superbowl.
Batman: Vengence - 5 - Really captured the Batman the animated series feel and style, great story, mediocre gameplay.
Metabots Infinity - 5 - Like custom robo but worse in just about every way. Fun, but everytime i want to play it, i think better and play Custom Robo.
Godzilla Destroy All Monsters - 2 Horrible horrible game, few monsters, lame moves, mediocre controls. Sad news as I am a Godzilla Fan. It's so unenjoyable i'd rather play the NES Godzilla game!
I know i'm missing some but hey, your bound to do that when you have a bunch of games.
SW-
