For OG shooter, look up Ikaruga. Top down old school shoot 'em up made by the best. There's also PN03, but its getting mediocre reviews. I'm for that one to hit the discount rack myself.
If you can wait 3 years, there's Project Unity from Lionhead Studios. That'll be a fun one.
I don't know mate - I guess I have to admit that the GCN isn't a frag box just right now. No bleedin' LAN games to play on, fer chrissake. Free Radical must have been pissed at Nintendo. I know I am for it.