FFS Someone beat me to Mirai Nikki and gurren lagann.
But I'll just nerd out here and put in anything I have that I feel are good.
Also, don't complain if I put endings in there too, because animes need a good ending along with a good opening.
Animes
Shakugan no Shana (3rd season opening I think).
Neon Genesis Evangelion(Inb4, don't complain about Shinji's character)
Hokuto no Ken (Fist of the north star)
Jojo's bizarre adventure (New series that came out in 2012)
Dragon Ball (Japanese) Inb4, funimation sucks in my opinion.
Dragon Ball z 3rd opening (Around time Gohan became the main character).
Angel Beats (Of course in my top ten favorite animes :3)
G Gundam
Gundam 0079 opening (I don't care if it's old, it's awesome)
Gundam 00 Season 2(I think this was posted before, but the link's broke.)
Ashita no Joe, an anime my dad watched as a kid and I did too.
My dad was a total anime fan until his 30s where he married my mom.
The Slayers, again another anime my dad was into. Infact I have some of the VHS tapes on the living room's bookshelves.
Magic knight Rayearth
Haruhi Suzumiya dance. How the hell has this not been put up?
Chrono Crusade
Fry me to the moon.
Gohan's Ssj2 theme.
I realize someone else posted Angel Beats, but it's still a good opening.
Now I'll stop because this post is probably bigger then I intended.
Originally Posted by Nanoir
Ohh i have that song on osu, http://osu.ppy.sh, osu is a music game full of anime OSTs. You guys should try it! It's really awesome And is elfen lied similar to Mirai nikki?