As I started saying in
this thread, backwards compatibility means that games stores ought to keep a healthy supply of the best GameCube games even after the Wii arrives (much like how PSX games were still around for a while after the PS2 came out). The problem is that the GameCube isn't as popular as the PlayStation was, so some stores may already be just letting their stock of GameCube games run out and then not even bother.
So if the Wii becomes the super-hot thing to own, then there may be a slight boost in demand for GameCube games that people passed on, since they couldn't be bothered to get a GameCube, but can now play because of backwards compatibility on the Wii. One thing I suggested was for Nintendo to rererelease the Player's Choice games.
But for games stores that won't ever look back, perhaps "Wiimakes" could be an option. For some games, not all - as people said, new games are preferable to using up resources remaking games that Nintendo fans likely have already played.
It's an interesting dilemma, I think. I may be speaking prematurely but if the Wii has a shot at being #1 you're seeing a jump from last to first, putting GameCube software in a possibly interesting position - games people want that games stores stopped carrying.
Of course, the key about the Wii is its controller - people will buy the Wii for Wii games, and less so for GameCube games. So "Wiiified" GameCube games would make them appealing. The trick is in the balance - which games, and how much should they be Wiiified?