What addons are available for keeping up Buffs in World of Warcraft?
Solution 1:
SmartBuff has been around for at least 3 years. Always worked for me when I used to raid (as a priest but works for other classes).
Solution 2:
AnnoyingBuffReminder. As the name says, it's annoying and will learn her to buff everyone / herself the hard way :)
Solution 3:
If she plans to do any healing, VuhDo has a lot of panels and options. One of these is the "BuffWatch", in which she can choose any buff and an indicator will show up here when it is missing from herself or a party member.
I have mine set to turn off all panels except BuffWatch when I'm not in a party.
Solution 4:
For your own buffs, AnnoyingBuffReminder is great, like Ondrej posted. I don't think it does Power word: Shield, but it does all the other priest buffs.
If you want to check your entire raid for buffs, I'd recommend RaidBuffStatus. You can use it for your own buffs as well, but I feel it's a little too complicated when you use it just for that.