Yes, the GCN version of Soul Calibur is by far the best. I've never used anyone other than Link.
other GCN fighting games I can think of:
Bloody Roar - this game is really good. Have you played it?
Def Jam - never played em.
Mortal Kombat Nemesis/Deadly Alliance/Deception - haven't played them (yet)
X-Men Next Dimension - this is kind of good. The controls are pretty stiff and wonky at times, but it had some cool ideas and nice big roster.
there's also a lot of Manga-based fighters on the Cube. A lot of them might be Japan-only. I don't know. I stay away from Manga. But I know there's Bleach, Naruto, etc games.
plus the Melee craze:
Super Smash Bros - I'm not a huge fan, but it's kinda fun. I suck at it.
Dreamix TV World Fighters - Japan only unfortunately. Awesome Hudson answer to Smash Bros.
Godzilla Destroy All Monsters Melee - freaking incredible.
TMNT Mutant Melee - it's Ninja Turtles!