Let's hear your favorite!
The ones I know of that brew in the cities:
I'm sure there's got to be more though.
So far I've toured Summit, and I go down to Flat Earth about once a month for Growlers.
I have to say Flat Earth is easily my favorite. They're so nice there, they'll sit and talk to you about their beer forever, you can tell they really love it. They are generous with the samples, and the growler prices are very reasonable. Plus I love going down there and being surprised by whatever new thing they've brewed up.