Sentai: Simply because the lyrics are so dead-on to what fandom is like,
http://www.youtube.com/watch?v=9XlrD6ROG7E

Kamen Rider: Going old school here, and it's not Black or Black RX! (although I love those, too),
http://www.youtube.com/watch?v=b7tNYHk5aWI

Other: Is there really any other choice?
http://www.youtube.com/watch?v=DuOrQko1c1w

SENTAI: Gokai Zenkai Dash from Kaizoku Sentai Gokaiger
KAMEN RIDER: I remember really liking all 3 Kamen Rider Kiva endings
METAL HERO: Tokusou Exceedraft from Tokusou Exceedraft
ULTRAMAN: Take Me Higher from Ultraman Tiga
OTHER: The Life from Tomica Hero Rescue Force

Kamen Rider - Black RX , I am not sure why i get juiced when i hear it.. but it's awesome!

Sentai - Sun Vulcan or Dekaranger

sentai - goseiger
kr - kr 000
ultraman - ultraman taro
metal hero - gavan
other - sazer x , gransazers