I've been to the Lighthouse Bar on many occasions to see the free shows, which I must admit are really good. Most of the barstaff and waitresses are fantastic, although if you're sitting at a table service can sometimes be very slow. Your best bet is to get a seat at the bar proper. The female bartenders are very attractive with very few exceptions, and are great at their jobs. I'm mostly a Sam Adams beer guy, so my tastes are taken care of, but I think the beer options are fairly limited. Mixed drinks, on the other hand, run the whole gamut.
Pros: good looking women, great free concerts
Cons: slow service at tables, erratic last call times