Add to that list, Smash Bros, Baiten Kaitos, Pikmin 2, Eternal Darkness, RE 4 (as mentioned), Ikaruga, Viewtiful Joe, Animal Crossing, Resident Evil 0, Mario Party, Metroid Prime 2, Mario Tennis, Paper Mario, Alien Hominid (also on PS2), Tales of Symphonia, F-Zero, Mario Golf...
Those are just exclusives (at least I think they all are). A lot of the other great games are there too that are available for all the systems, like Splinter Cell, etc. And a lot of the multiplatform games are much better on Gamecube than PS2 because it's a more powerful system and has the greatest controller of all time. Considering it has a small, but decent list of spectacular exclusives and a long list of multiplatforms the $100 entry price is an absolute bargain, in my opinion.