Hair. Hair is a guilty culprit of sucking up render time, also, uber lights if you used those. Anything with a transparency (hair, eyelashes, etc) sucks up time badly.
Oh, one thing that may speed up, in your render settings, have your ray trace set to 1 instead of 2. For such small pictures, you will not see a difference, but if you were to do a large poster size print, that is where that matters.