Not been back for a while but off the top of my head – Tin Angel on Spon Street is small but nice, wih emphasis on live music. Browns on Earl Street is also good – bigger bar but decent drinks and nice atmosphere. If you're after a proper pub with a wide selection of ales then Whitefriars on Gosford Street, just down the road from Browns is probably your best bet.
After hours? Probably Kasbah is the only bet although not been there since it got done up and changed its name from the Colosseum a few years ago!
Umm, apart from that I'm struggling and I grew up in the place!