Priest leveling in 4.0

[Somebody]

So patch 4.0 rolled over while I was leveling my priest who is now level 27. I have no idea how to spec her so I thought I would give Disc a shot. So far Penance is an all around OP spell and with increased mana from speccing disc, my rotation looks like

PW: shield > pull with smite > Holy Fire> Mind Blast > Penance > Wand
Pop Archangel every time its up for 3% mana return.

I'm finding I need to drink way less often than I did prior to the patch, but I still have to drink sometimes.

I'm just wondering if any other spec is worth trying. I'm mainly looking for a fast and efficient spec with the lowest downtime. Currently I only pull 1 thing at a time. Not sure if thats just because I'm only 27 and it gets better or what, but I'd like to be able to pull multiples or chain pull things.

[Haedess]

When i lvled my priest i did shadow, but then we had spirit tap. Now that's gone i am not quite sure which spec is the best. Run with what you think is most fun. My recomendation