Well, I've read through the entire thread and would like to add some thoughts.
First of, try to avoid tricks that uses the bar itself. I don't know for what kind of bars you are performing for/in/on, but the bar itself is always wet/sticky/dirty/needs to be cleaned etc. So do magic in your hands, or spectator hands. If you perform for nice quiet bars, during the day, where you can actually set up a close-up pad, than please do.
Secondly, do magic that is chest height. Depends on the hight of the bar and your own height, some tricks will not be seen at crotch level, so perform nice and up at chest level.
If you cannot be heard, than perform highly visual effects that don't need patter, and use your body language and mime to inhance the effect.
I was performing in really loud bars and clubs (think "White Sensation" kind of party's), and I would recommend you to get any type of "Ring Flight" effect (ring to keychain in your wallet), that one is quick, visual and doesn't need any patter. Also Asher Twist, really nice one, specially if you add a little visual at the end (aces first changes color on the back, than changes faces into kings). ACR is also good. De'Ring... etc. They are all quick and visual and need no patter.