Benadryl and Tylenol PM are the same thing: diphenhydramine. A lot of sleep aids are. Check the ingredients before you buy; if it's diphenhydramine, it's not going to help you.
Doxylamine Succinate is what is found in Unisom and some forms of Nyquil.
Melatonin is naturally occurring and I've heard many success stories with it.
I love Ambien, but it's not right for everyone. But don't be *afraid* to try it. But do make sure that you have someone in the house with you the first night or two that you take it, because people have been known to sleep drive, sleep eat, sleep internet shop, etc while on Ambien. I never had those problems, but better to be safe than sorry.