1- Molgera from TLoZ WW (not the hardest one, but fighting it was cool and cool music)
2- "You'll meet your dad soon, Fox."
3- Mizar in Asteroid, Jet Force Gemini. One of the hardest bosses i've ever played.
4-Volvagia, Bongo Bongo, Twinrova and Phantom Ganon from Ocarina of Time.
5-Alec Trevelyan, Cradle 00 Agent, Goldeneye 007. THAT F**CKING CRADLE.