If you work anywhere in or near River North, the Green Door is a must do for lunch. Whether dining alone at the bar or with a group, Green Door accommodates. I have always been a solo diner, and I sit at the bar. My favorite things there are the quesadillas (made with buffalo sauce inside...mmmm), the burger (it's what they're famous for), the buffalo chicken sandwich, the pizza bread, and my own version of the pizza bread made with avocado and swiss only. The bloody mary's are the best in town (made with a splash of guinness for body).
Pros: Great food. Great service.
Cons: lunch hour isn't long enough.