I see a lot of different ideas from the girls here on what they consider is too high for a heel. I am 5' even so to me, anything under 3" is "flat" or darn close to it. I wear 4" heels on a regular basis and don't bat an eye. I even have some extreme 8" platform/heel combos that I joking call "stipper shoes" because they probably should be that I wear out very very occasionally or with Halloween costumes.
So what is your max comfortable height?