We've all read Brooklyn Based's excellently thorough guides to coffices--coffee shops that are particularly good for working--but maybe you like something a little stronger with your free wifi.
I know I do, so here's a short list of my favorite bars for working all around Brooklyn, or at least the parts of Brooklyn where I spend all my time. Of course, more research is needed, so look out for updates and suggest your favorites below!
For computery work
Pacific Standard is a lovely place! I've totally been there on a Tuesday evening surrounded by other folks working on laptops. Maybe that destroys the social nature of going to a bar, but it's kind of nice to know you're not the only one working.
Abilene is my personal favorite, since it's right up the street from the Brainery. During the warm months, you can sit outside and procrastinate with excellent people watching. Good bar food and happy hour too!
For "business meetings"
Habana Outpost on a sunny spring afternoon is kind of the best. This place is busy, pretty much all the time. But there are some rare days early in the season when, if you sneak in before the after-work crowd gets there, you'll have plenty of space and time. No wifi, but the sunshine and cheap Sixpoint more than makes up for it.
Soma and I usually end up across the street at Der Schwarzer Kolner, where we get all our best brainstorming done. (It is often full of babies though, so plan accordingly.)
(Note: I really want to call these "barfices" but everyone seems to think that is a bad idea.)