BWI is one that I was pleasantly surprised to see 'street pricing' at. PotBelly had sandwiches for $3.69 and bottles of water for less than $1.50. Compared to ghetto LAX, I was saying Wow! (I understand BWI is run by BAA)
While SFO is not cheap it's not overpriced either, and there are some great food options.
Not to hijack the thread, my other issue is vendors that have an exclusive contract to run all the concessions. Example: HMS host running an airport Starbucks with drinks at least $1 over a regular Starbucks while their employees run the machines and have 1/2 the knowledge of a real Starbucks employee.
MSP obviously has a good system in place: they have BOTH Starbucks and Caribou as well as other vendors serving espresso.^