I've already written a post (if not several) here about Holy Paladin Loot in Ulduar. And Pallymar compiled an Ulduar Best-in-Slot Guide too with additional discussion on the items.
If these guides are quick easy reference guides, you could always ask the question: but why this guy is saying that item is better ? If I hope you'll give us enough credit to believe in our choices, sometimes you will have to make your own choices and I would like to give you tips for that.
It happens that Sailan at Banana Shoulders just posted the perfect post for that:
Choosing Your Attributes. You can read there a very detailed and well written discussion about the merit of each stat for a holy paladin, spell power vs. spell crit, you'll find all of that there. And I definitely agree with Sailan who, once again, deliver us a very good piece of work.
I'll be off for the weekend, so I wish you all a very good weekend, and see you on Monday for a new post.