I suggest Autobar for holding your basic items without tying up your action bar slots (it holds things like potions, buff items, hearthstone, mount(s), etc.
There are other Priest-related addons that you might find useful:
Cirk's Shadowshift --
http://www.wowinterface.com/download...fo.php?id=4542 -- Shadowshift places the Shadowform spell button onto the shapeshift bar, just like Stealth for a Rogue, or like the Druid's Bear, Cat, and other shapes, allowing you to use it just like it was a real shapeshifting skill. Free up an action button slot today!
Shadowoff --
http://www.wowinterface.com/download...fo.php?id=5859 -- This is a small AddOn which automatically cancels shadow form when a Holy spell (or any other action that requires to be out of shadow form) is cast.
Healbot Continued --
http://www.wowinterface.com/download...fo.php?id=6096 --
HealBot allows for 20 key mouse combinations to cast any beneficial spells.
HealBot allows for 20 key mouse combinations to cast on disabled bars.
HealBot can track and display who has aggro
Any usable item can be added to all combos.
Target, Focus and Assist can be added to all combos
HealBot can be used for decursive functions
HealBot can be used for monitoring buffs and buffing
HealBots appearance can be configured and preferred appearances can be saved as skins.
HealBot can show party/tanks/checked targets/extras in a raid, extras can be filtered and sorted.
Multiple HealBots in a party/raid sync incoming heals.
HealBot will accurately range check at all times for spells and items.
HealBot has a built in res monitor and is compatible with CTRA (CTRA not required)
HealBot has a SmartCast out of combat option, this will cast a spell in the following order..
1. res
2. decurse
3. buff
4. heal
5. user setting
A good action bar addon is good to use as well.