this is the hybrid I found usefull.
absalution is worth having points in but not at the cost of high heals.
you dont need imp shield because you should not be taking any hits if your tank knows how to play.
putting points into increasing your % is more for damage than plus healing and once your 70 you wont have a whole lot of crit gear unless your shadow.
Imp spirit is usefull but if you read it, its based on the amount of spirit that your casters have to increase the damage output. Most mages and locks dont have a whole lot of spirit that I have found. how ever that being said if you want to go deep disc then its a must have.http://www.wowhead.com/?talent=bxgMdhZfVt0s0qVuVo
full holy build
you could play with a few of the points in this build if you wan't the % increase go with inspiration for your tanks in raids and heroics.
you can go with mental ag but the 10% once you have 12k mana pool is hardly notice able.
pvp hybrid build http://www.wowhead.com/?talent=bxgh0hg0MZfVt0s0qV0h
this is a pvp hybrid build that I used till i started going disc BR is really great so is SW but some like the heal for 8% over time if you get hit.
any way i am half a sleep and should start getting ready for work hope this might help a little.
on my old server I had five priests that i would all ways talk to about differant build types to see what they are doing at the time.
have a good day Gentle