On their Boeing 717 planes, Midwest Airlines has a very comfortable 2 X 2 seating configuration in coach. Using the same Boeing 717, AirTran Airlines squeezes in another seat, going with the 2 X 3 configuration. The business class seats on AirTran are only 1" wider than the coach seats on Midwest.

This isn't a commentary on Airline economics - it's just a thank you to Midwest for making my coach flight comfortable. I hope other airlines will follow their lead, but given the current state of the commercial airline industry, I'm not expecting anything anytime soon. 

As a side note, Seatguru.com is a great place to go when you're choosing your seat.