I find aura’s to be brilliant permissions slips for people and to reinforce a behaviour that person wants in play. People have a terrible excuse for avoiding fun things which is “oh my character wouldn’t do that”, well now they have a card or ribbon saying they totally would.
In terms of my favourite, in general I think Hallowings are more fun than Anointing. Anointing has the better “mechanical” effect as it’s a source of spiritual strength but my personal opinion is that if someone is going for mechanical benefit over roleplay fun then they’re on a road to disappointment.
There are a number of Hallowings I really like, I play a Courage priest so I’m a little biased.
First is the Hallowing of the Irontooth which is "You feel driven to expose cowardice and corruption regardless of consequences.!
The other is the Hallowing of Inga Tarn which is “You feel an urge to confront and defeat dangers that threaten the innocent.”
I do like all the Courage Hallowing, they push individuals to conflict and that is fun in game, they work really well for lots of character styles, from bombastic to quiet (I like the idea of a quiet academic who is utterly intractable, just politely refusing to go along with things they believe is wrong)
Other Virtues, I think the Vigilance roleplaying effects are big and clever and not used enough in play. There are so many ways one can go with them.