Fatheads is a great restaurant with a great beer selection, but one big drawback: the crowds.  I have stopped by at 9:30 on a Monday night, and had a 45-minute wait.  I have found that the crowds have gotten larger and larger over time, to the point that it's not that enjoyable anymore.  I'm all for having a few beers while waiting for a table to become available, but it ends up that you are crammed in the bar area for 2 hours, and you end up having too much to drink before you eat.  In the event that you DO get a seat in a reasonable time period, try the South Side Slopes Headwich: Kielbasa and Pierogies on a sandwich can't be beat.