With over 18 Commodore 64 titles already released on the European Virtual Console, it's a safe bet that we'll get a good idea of what's in the works simply by looking at what Europe already has. They've seen a steady stream of releases since March 28th of last year, when Uridium and International Karate made their debut, since then adding such classics as Jumpman, Boulder Dash, California Games, and the Last Ninja series.
Despite having been heavily immersed in Commodore culture back in the 80's, I am honestly hard-pressed to name any large Commodore exclusive titles, having played mainly ports of games that were created with other PC systems in mind. Add to that the fact that many of the games I played back then were text-based adventure titles, and the list narrows down even further.
When it comes right down to it, there really aren't that many Commodore 64 titles that you can't just find floating about the internet somewhere, so I'm not sure I can see myself forking out $5 for a Commodore 64 game, as novel as the idea might be.
Take a look at Wikipedia's gigantic list of Commodore 64 titles and see if any of them tickle your fancy, or at least stir the sort of fond memories that are worth 500 Wii points.