Well Rosario+Vampire II is probably out of the question unless you've read the first part.
Claymore is pretty good for the most part until it gets kinda strange, but that isn't until much much later on.
It currently "ended" in Japan, but supposedly it's going to continue on soon.
But it's safe to say that it'll be the one to 'finish' the soonest out of those choices going by Viz releases.
Blue Exorcist would be another good choice since I did like what I watched from the anime and it has the least amount of chapters out so far so it should take the shortest time to catch up on.
--
O brilliant blade of coldest steel, rend the infinite darkness and crush my enemies to nothing... SAVAGE WOLF FURY