Depends on the situation really.
Attack you use either Blow or Mana Shock, but against bosses you'd probably have to use Increased Range if you wanted them to work (Blow and Mana Shock don't seem to go off when used against bosses...bug or not, I don't know).
Defense almost always use Decrease Damage, with Reflect on bagis and AKs (unless they're fail, and are getting hit hard). Of course, just like a seg, listen to what your buffees say. If they want something different, and you are in a giving mood, give it to them.
And, just like segs, the singles are MUCH better than the groups. Don't even bother learning the groups, your singles cool quickly (and since they aren't time-based, no need to worry about them running out before you get everyone buffed).