I recommend Summer Breeze Hotel on Soi Sansabai. It's a 30 odd room guesthouse located at the end of Soi Bangla, gf friendly so no payments needed to get girls back to your room.
I now live here however this is the only place I, my brother and friends ever stay or stayed at. Good prices, great staff and the owners Bill and Kurt are great guys.
I definitely recommend this joint.
http://www.summerbreezehotel.com/