Christ, I have a lot of faves, and this is considering that I usually skip OPs and EDs when watching. It's only when the music feels epic enough that I actually sit through them. In fact, I may have missed a few.
OPs:
Motteke! Sailor Fuku - Lucky Star
Tori no Uta - Air (cried manly tears at the end)
Sketch Switch - Hidamari Sketch (oh God, I can't stop clapping to this and swaying like a kid on a sugar rush)
1000% Sparkling - Negima!?
Hishoku No Sora - Shakugan No Shana (OH GOD SHANA'S HOT)
Re-Sublimity - Kannazuki no Miko (anime sucked though)
Innocent Starter - Nanoha
Eternal Blaze - Nanoha A's
Dogfight - Initial D 4th Stage
Noizy Tribe - Initial D 4th Stage
Higurashi No Naku Koro ni - Higurashi 1st Season (USO DA!!!)
Naraku No Hana - Higurashi 2nd Season (moar epic version can be seen
here. Warning though; there's gratuitous worksafe pics and Satoko's uncle being chased with a bat.)
Bouken Desho, Desho? - Suzumiya Haruhi no Yuutsu
Face of Fact REVOLUTION - Baldr Force Exe
Hitomi no Naka no Meikyuu - Yami to Boushi to Hon no Tabibito (also known as the role where Mamiko Noto is a badass and :fap:s to her sister)
Dramatic - Honey And Clover 1st Season (series in general made me laugh and cry manly tears)
Colorless Wind - Sola
I Say Yes - Zero no Tsukaima 2nd Season (OH GOD LOUISE IS flat lol
)
Colors - Code Geass
Nightmare - Jigoku Shoujo 2nd Season
EPs:
Yoake Umare Kuru Shoujo - Shakugan no Shana
Agony - Kannazuki no Miko
Hare Hare Yukai - Suzumiya Haruhi no Yuutsu
Sensitive - Step Sister (wait, WHAT
)
Fruits Candy - Card Captor Sakura
Mellow Melody - Sola