If you don't fancy Hat Yai try Songkhla which is a sea side resort.The Asia Pavilion Hotel is very good and has its own massage parlour inside.
There is small bar area called the Darkside (10 Bars) near/on Sadao Soi just round the corner from the hotel.If you want a realy cheap hotel then go to the Royal Crown which only charged 490 Baht per night on my last trip.
The Buzz Stop Bar is an Irish bar and does great food.