I have not [experienced discrimination], but then, I'm a straight woman.
I do have friends who are gay, bi, and transgendered, however, and most (if not all) of them have experienced some discrimination in public places. For example, I was recently with a friend at a local restaurant, and the waitress was extremely rude to my friend -- she made a remark to another patron (in our hearing) about "fags"; we had to wait longer than other patrons for service.
We were quite angry, and walked out. We were told no manager was on duty that night, so we couldn't complain directly, but I called the restaurant the next day. Management didn't seem terribly concerned about our experience.
(female, straight)