Just a quick plug for a new blog I discovered by accident today. The content is something I was going to cover this weekend after a TS discussion with a guildy who is new to the cloth. Andreas over at Lightning and Lava, has made a fine post from a resto shaman point of view and the majority of what he has said holds true for us priests and I see no point in re-inventing the wheel. So take a quick read of his post at Lightning and Lava - Restoration Glyphs, Gems and stats.
That covers the basic gem info as well as the basic principles of the main stats, personally I always aim for the gem bonuses and always put Brilliant gems (Inferno Ruby or Chimera's Eye) in red sockets and Purified Demonseye in Blue Sockets. The yellow socket is a bit of a free for all where I'll use either Reckless , Potent or Artful Amber Topaz depending on my needs for haste, crit and mastery. Unlike our totem stomping comrades, we need stats in a slightly different order and there are different priorities for Holy and Discipline too.
For Holy priests the stat priority is:
Intellect > Spirit (until regen is not an issue for you)>Haste (to 12.5% raid buffed)>Mastery>Crit
For Discipline Priests priests the stat priority is:
Intellect > Spirit (until regen is not an issue for you)>Haste=Mastery=Crit (keep these balanced)
As a general rule of thumb you should enchant Intellect or Spirit where ever possible, the notable exception is chest where +15 stats is a better alround enchant than the spirit only one. Put +speed on boots it can save you and your friends in raids encounters trust me.
I'll cover glyphs in a later post as well as revisit the info here in more detail