Something to think about is the filter size of the various lenses. Your choice of 80/1.9 and 150/3.8LS is good because you'll be able to use the same 67 filters. Ditto for the 45/2.8 if you eventually want a wide lens, or the 150/2.8 (probably the nicest lens for the system barring the $$$ 200APO and 300APO, and maybe the 120 macro).