I've always really liked Hua Hin and think it is worth the side trip.
Its a different pace from Bangkok, beer is cheaper and the girls are older I guess, still a few diamonds to be found. Main strip is Hilton/Soi Bintabaht, if you do a couple of searches on YouTube you'll get a good idea of the area and its best to go out later at night, Panama and Hilton are good places to pick up.
There is also Soi 80 which is a area about 5 mins tuk-tuk from Hilton. Its ok during the day, bars are dirt cheap but full of the worst kind of pissed, jaded, boasting Ex-Pats. One decent bar called Nana Bar was run by lovely Thai MILF, her girls were nice enough if you like tattoos.
Enjoy!