I ran a pally/4 discs up to around level 85 and atonement was OP. Rarely had to cast an actual heal. I hear it isn't as good at 90, though. I disabled all accounts except for my main so can't go into wow and get my macros but I do have a backup copy but not sure if it was the final one I used.

/castsequence reset=8/target [nochanneling] penance, Shadow Word: Pain, holy fire, renew, Power Word: Solace, smite, smite, smite
/cast [nochanneling] [target=targettarget] Power Word: Shield
/cast [nochanneling] Shadowfiend
/cast [nochanneling] !Shadow Word: Death