so far i've ridden 58s. I'm about 6ft, pretty long legs. bikes have had 58cm top tubes, i've ridden them with 90mm stems and a decent amount of seat tube showing. never had a comfort problem.
but i notice that lots of guys ride smaller frames, including my hero:
i am definitely not that far past the head tube when i lean over.
so i'm thinking of trying a 56. thoughts?