Buttermilk Bar
The main local for South Slope folk. Free pizza on Wednesdays. Sadly, the photo booth has been taken away.
Commonwealth
A new bar worth looking into in southern Park Slope. Good jukebox.
Great Lakes
A Park Slope best, but a bit too crowded on the weekends.
Loki Lounge
A sports bar with a pool table in the front, and a pleasant lounge in the back with many sunken but elegant couches. This lounge has a good atmosphere for a date or a group of friends almost any size.
Patio Lounge
A wine bar that makes a great sangria. It has a very relaxed atmosphere and the music is soft enough to allow talking. On the weekends there is a DJ providing an eclectic mix of music. Out back there is a very nice garden area that is especially tempting during the warmer months. The best part is that they will even let you order take out to the bar and eat it out back! Patio only serves wine, beer and sake, but if you are looking for something with more of a kick ask for the Japanese "rice vodka".
Southpaw
Park Slope music venue.
Tea Lounge
By now it's a tried and true formula: a big room with lots of thrift-shop couches, an Italian coffee machine and the expertise to use it to make a well crafted mocha. Pastries, bagels, wine, hard liquor, smoothies. Throw in cool ceiling fans and free wireless internet access and you're set for a great morning windup to NYC sightseeing. $2 regular coffee is just the bonus.
Barbes
A truly wonderful neighborhood bar and live music venue. Barbes tends tends to bring in bands that play early swing, Balkan brass bands which are fabulous, and singer/songwriter types. The shows tend to be very high quality, and the drinks are reasonable, and well made. The help is extremely friendly, and will make you feel at home in no time.
Total Wine Bar
A very upscale but reasonably priced wine bar that also serves fine cheeses among other small plates. The atmosphere is excellent for a date or just a great place to hang out with a few friends. It is not particularly conducive to larger groups however.