Shake is (or at least was) the most partnered compositor for Maya in the big ish studios, but its hardly a cheap purchase. Pretty sure version 2.5 is the last windows version. Silicon Grail's RayZ was another one that played nice with maya, but alas Apple gobbled them up too.
Digital fusion(again not cheap) or After Effects then I suppose. Personally i dont like Combustion, though I've not used it since verision 1.1