A common question. First off you can get RE4 wii version which has motion controls for aiming, probably a lot better than the gamecube version.
That said, F Zero GX, Soul Calibur II and the 'Zelda Collectors Edition' are all fantastic GC discs. Gamecube controllers are very cheap to buy used. I recomend the wireless Wavebird if you don't mind giving up the rumble feature.