I too want gamecube games. It'd mean I could finally get rid of my Wii. The only reason I hang onto that thing is for Mario Sunshine and Skies of Arcadia.
After that, as many Wii games as possible that use the classic controller. I use the Wii U gamepad as a screen a lot so that's best for me. Last Story would be good. If they release Xenoblade Chronicles I'll be annoyed as that's the main reason I bought the new 3DS.