[noa]

First, I'll want to know what the atmosphere is like. There are plenty of places I would rule out just by reading that its a trendy lounge, etc. I always want to avoid places that get described online as overcrowded and/or loud. Initial descriptions are very important.
Next, I'd want to know what kind of drink selection they have, and how many beers are on tap.
Other than that, I'd be interested in knowing if its the place I could spend a couple hours with some friends and shoot the shit.
I look on Yelp or other websites for reviews usually. There are plenty of good resources describing the bars where I live (NY). So I would say internet reviews are very helpful.
An example of an ideal place: I really like going places that have games and snacks. One of my favorite places in the city has a great beer selection, little chocolate candies (like Hershies minis) and pretzels or chex mix throughout the bar, and you can play Connect 4, Battleship, Boggle, Jenga, Scattegories, and other games while you're there. They don't have huge flat screen TVs, just little ones throughout the bar, so it might not be ideal for watching sports, but you could certainly do it there if you were so inclined. I think that place is great because it has great selection for beer lovers, games for people who just want to hang out, so it suits guys and gals.