Path of Harmonious Balance will get you Fists of Light. When used on an Undead monster, it deals 2d6 damage.
It also applies a Healing Curse (on every monster, it only does damage to the undead), which heals you for 1-2 points of damage every time you strike the cursed monster. Doesn't appear to be a save on the curse (and from what higher level monks say, it works on just about EVERYTHING)
Light-Light-Light finisher is a Mass Cure Light Wounds spell, basically, and heals you (and anyone around you) for 2d4+something heal. This IS affected by Devotion-type items, abilities, and the cleric empowered healing. I have a Devotion II ring on and i've seen it hit for 13 so far. (Not sure what the modifier is. Probably half your monk level +wisdom modifier like everything else)
Harmonious Balance also gives you access to Remove Diesease, Lesser Restoration, Remove Curse, Remove Blindness, and Revive - All of which cost quite a bit of Ki (and the revive costs a good deal of health as well) but are handy in a pinch. Usually, I have to meditate to get Ki first (if I get blinded in the middle of a fight, it's goodbye, pretty much, unless I happen to have 30 ki on-hand, but I usually spend it too fast for that to happen except on multiple zombies/oozes)
I've found it incredibly valuable myself, but I admit I have been somewhat interested in all the damage/debuff potential of the Dark Side...