MCI is a great example of an airport with competitive rates. Not that you'd want to retire in Kansas City.

A good start would be to look at a route map for Southwest. Any Southwest Airlines city should be reasonably cheap. Then look at Travelocity's Dream Maps feature for that city to verify that advanced purchase flights are in fact reasonable.

Compare PHL to RDU to see the non-hub/Southwest effect in action. When I looked at it today, you can't go west of New Orleand for less than $200 from PHL.

Another good comparison is CVG vs. CMH.