40 is the obvious milestone as many have stated (level 44 here and still don't have mounts for all my guys ). My real milestone though is getting my troll shammies (i have 3 trolls, 2 orcs in my 5x shammy group) to exalted with org so that I can have wolf mounts on all of them. I'm a wolf freak.

Right now my trolls are about 7k rep short of exalted. Working on grinding those locations for some more rep. Need to hit some of the more org oriented zones on the eastern continent.