Even without GCN compatibility, you can still soft-mod the hell out of them.
NES, SNES, GB, GBC, GBA, Genesis, Neo-Geo, TurboGrafx-16, 2600, 7800, Atari ST, all sorts of stuff. They support Netflix, Hulu, YouTube, or you can install WiiMC, the homebrew media channel, and stream video from your PC.