I've never been one before, so I'm definitely new to the skills, etc.
After you cast your divine power and build up empower (or whatever they're called) - do you NEED 3 of them to get the empowerment buff? Or can you still get a buff when you only have 1 or 2?
One orb (stack) is enough to trigger the empowerment buff to an encounter power. Each orb up to three gives more benefit. I can't remember a specific one, but most encounters say something like receive x % increase for y stack of empowered used or something similar depending on the effect.
Comments
Also, in case you missed it:
http://nw-forum.perfectworld.com/forumdisplay.php?1401-Cleric-Class-Discussion
Probably lots of helpful info in there.
Enjoy your DC!