i might be biased, but i love xSnes9x. Current favorite rom: Arkanoid 2
Maybe Gatsu's zsnes port might take the mantle if he can finish it. I have high hopes for it.
Ok taking my stuff out of the picture, i think id have to go with KawaX, ScummVMx or Xenesis
homebrew is....none yet..but that new Star Wars game is looking quite nice