Thanks everybody for the recs and the welcomes! After doing a lot of looking around and playing of different guitars, I ended up buying a Blue Ridge 160 at the Old Town School of Folk Music here in Chicago. I love this guitar--it's based on vintage Martin designs, it looks and sounds great. Now comes the fun part--learning how to play it! So far I'm learning very simple chord progressions--Helpless, Franklin's Tower, Knockin' on Heaven's Door, each of which is just a few chords over and over. And playing scales. I can't believe I waited so long to do this, it's so much fun.
The Old Town School of Folk Music has classes in flatpicking, bluegrass, and even the Grateful Dead, so once I get some basics under my belt I will be checking that place out some more too.