I easily fall for the ones that get portrayed from a more humanistic viewpoint.
Yamada (Honey & Clover) or Haruka (Kimi ga Nozomu Eien). I can make them forget all about Mayama/Takayuki. 🙂
If we're talking about who's the best piece of eye candy ever created, that's Aya or Maya. (Tenjou Tenge)