Just an update to the original post - the Dark Horse no longer exists,sort of. Its Cavanaugh's Head House. Same building, just under the Cav's ownership group now. Still the same general feel and vibe, but the name has changed. One of the better soccer/football bars in the city. My friends and I meet up there every year for boxing day, and even at 7:30 it's got some people in it already for the early games. Paul, the bartender upstairs (normally) is an awesome dude - and no, I'm not Paul.
For the Craft beer crowd - some of the better bars in the ctty, in my experience, have been (in no particular order):
Monk's Cafe (obviously) - Consistently voted one of the best bars in America - 16th between Locust and Spruce, if memory serves
Varga: 10th and Pine, just south of Patco stop on 10th and locust - great taps, good happy hour.
Strangelove's: 11th and Locust (i think?). This place used to change names and owners every 6 months, but has always had good local selections.
Bainbridge Barrel House: 6th and Bainbridge(surprise!)
Institute: 12th and Green
Prohibition: 13th and just south of Spring Garden
Misconduct: 18th and JFK is a good spot for soccer as well, but its a Gooner bar.
Bishop's Collar: 24th and Fairmount, good selectiona nd not far from the Museum, if you need a good beverage after
Good Dog: 15th and Locust - bit of a hipster haven (or was, been a while), but good beer and great burgers.
Jose Pistola's 15th between Spruce and Locust: Good ameri-mexican food, good taps. Liverpool supporter bar.
Bru: Chestnut between 13th and Broad: Food used to be better, think they changed chefs. Great selection of German beer and american craft though. Decent Happy hour, as well.
I'm probably forgetting few, but those are the ones i used to go to pretty frequently while i was working downtown.
Cant help but feel a bit homesick as i make this list. Cant wait to move back.