The conventional wisdom with all the recent patches is that it's much more productive to quest then to grind.  Even when it comes to AOE grinds, it's still better to just do the quest.  Perhaps that is true.  But what if you have an alt who you just use to DE things.  He's level 44 and you don't feel like doing quests which you've already done recently with two other alts.
Well if he's a mage, why not AOE grind.  I've tried this with my mage when I was in my level 20's.  At that point I did not like it at all.  In fact I hated the whole frost things.  Now at 44 and with tons and tons of rested XP, why not AOE a bit now and then and get to level 50, while I keep leveling my main through the Northrend, and take my time there to enjoy the quests.

So I've specked my mage frost AOE, and some initial AOEing proved to be quite fun.  It's soooo nice to have the ice barrier.  Before it, it was always a very close call when I did AOE.  Now it's much more practical and safer.  I will tweak the spec tonight, and will do some more murlock killing.

At the same time, it gives me an idea to about my other alts.  My paladin can also gain a few levels this way.  In fact he was my first AOE successful experiement, I leveled him and did most of the questing using a proteciton spec.  My biggest question is can I do the same with my druid.  I've read some posts, and it may be possible to grind him as AOE.  I should try feral, and balance perhaps to see which is more viable.