Personally, I went with the 35L, 85L II, and 135L (the classic 'holy trinity' of fast primes).
I beg your pardon OP but could I add a question to everyone here (in reference to Mr. Neuro's statement, may be he will also jump to share his understanding/opinion here).
Why does not this "holy trinity" include the 50L? Alright, 85 is 50mm more than 35 and 135 is 50mm more than 85. So they are equally spaced. That may be one logic (not a very strong one though). But is there any other reason to exclude 50L? We could have an "unholy foursome" (ok that did not come out right)....