http://paragon-wow.com/
We fought Halfus with the Slate Drake (A stacking -3% healing debuff) and Whelps (Whirlwind at 30% health). The berserk timer was quite tight and we needed a few pulls to down him.

Tracklist:
Takanashi Yasuharu - Guren no Ikari
Kalafina - Love Come Down

UI:
Nugcombobar (holy power tracker)
bartender4
Blizzard raid frames
Powerauras Classic