I voted "they are the same", because really, they are. I had been hoping to play it on the Wii, but being as I haven't been able to get a Wii, and I was really tired of waiting, I just got the GC version. It was fantastic, and as far as I can tell, the only graphical differences are that on the Wii version there is 16:9 support as well as 480i.
If you already have a Wii, I would get that version, if not, I would get the GC version. You won't really miss out on anything taking the GC route, and besides, that way your first Wii Zelda game experience will be the one made specifically for the systems power and controls, (the one they've stated that has been in development for the last year or so).