Got him today, it was my 65th attempt of all time. I think my new bow/gloves did the trick (+20k DPS) I'm at 60k dps w/o sharpshooter, and 110k dps with it.
I tried for an hour and half before work, best attempt being 24% in phase 3 (I was dumb and didn't dodge a fireball.)
Came home from work, died first try, second try did it to perfection. Inferno diablo is dead! Sooooo stoked. I didn't do anything on my DH for a couple days because I didn't want to lose the waypoint in front of diablo's door. Now I can use him to farm again!
Finally beat the game! on to leveling my barb to 60, then starting a monk in hardcore :P