I'm 5'6" as well, so not that tall but several inches taller than most of my girlfriends. I wear heels all the time, weekdays and weekends, and sometimes I feel a little monstrous, but most of the time it doesn't bother me.
I'm 5'10", and I do spend most of my time in flats, but that's more due to my general clumsiness!
I sometimes wear boots with 3-4" heels in the winter, other than that I really only wear heels for special occasions.
I did a search. I didn't see a thread specifically on this . It may have been asked in other threads but it would take some time to search through all of them. I'll glance through some of them though.
I'm 5'10" and mostly wear flats because my style is very casual (at school, running errands, . But I do wear 3" heels to work and if I'm go out somewhere, that requires me to be a bit dressier, on the weekends.