Good to see that you picked some of the more obscure Gamecube titles. Before I go on, I'd like to issue a public health warning: if you voted for Killer 7 having not played it before, remove the vote, then wash your hands thoroughly. I played it briefly on a friend's PS2, and it is total dreck. Those who voted for it having already played it, we may have already lost you. You have been warned, forums. (Now I'm worried Karl will edit this post out of spite.)
I'll vote for Star Wars: Rogue Leader because I never had a chance to try it - does it still live up to everyone's fond memories? I think Battalion Wars would also be an interesting discussion, but based on the comments so far, it has no resonance with people.
And for the record, TYP, if Billy Hatcher were on the poll, that would get my vote. It is a curious title with a bizarro twist on platforming that everyone owes to themselves to play.