I posted on this thread a month ago, and as it is still going, I would like to say something to the #1 (Never heal in combat, period) advocates, along with those who think that healing should only be reserved for bad luck or mistakes.
If you never have to heal in combat, your GM is being too easy on you.
I'm probably going to get some flak for saying this, but chances are your party is either optimized enough to need a higher CR to challenge it or a GM that will play monsters/NPCs to their full effect. Granted some monsters are mindless or too stupid to use tactics, but most aren't. I often see monsters encountered in strange and disadvantageous terrains. Kobolds should attack from ambush and with traps. Hobgoblins should fight as a team. Dragons should have plenty of room to fly. A discerning opponent should probably try to kill the arcane caster in the first round if he can. A monster with a wisdom score above 5 should roll a heal check to see if a dropped PC is dead or not. If they succeed: coup de grace if not threatened. Oh...and use those special abilities like poison on hit and so forth. I've seen GMs skip things like that they that either from neglect or to "be nice" and turn the encounter into a cakewalk.
It has been argued that having a healer is a crutch. No more than always having somebody buff you. If your arcane caster goes down to -8 in the surprise round (if you say this is impossible either you cheat, you lie, or you've never had a GM worth his salt) and the fighter and rogue don't get their haste, and with the additional loss of 1/4-1/6 of the party's action resources, they've been effectively castrated.
I am not trying to suggest that every encounter should put somebody below 0, nor am I suggesting that healing and buffing are the same thing or equal in value. I am saying that having somebody who can slap on some serious in combat healing (i.e. nothing less than 'Heal' at higher levels) can be necessary at times, and if it isn't, your group isn't doing it "wrong" per se, but I would submit that you aren't being "challenged."
A last note is one of roleplaying: people have noted that it can be fun to play a dedicated healer. I this is true, but it isn't for me. However, regardless, I do normally play Lawful Good characters and the typical PC is thought to be 'good' battling 'evil.' If you are a good cleric serving a good deity, and you have an ally near death, can you morally not heal them in order to lay the smite on somebody? I don't think even Iomedae would be happy with that, let alone a goddess like Sarenrae. Frankly, I think that's the sort of thing that gets clerics stripped of their powers.