I've heard great things about Columbus, OH. Never been there but sounds like a great midwest city with an affordable cost of living and nice college town (The Ohio State University).
Honestly one of the under rated large cities in the US is Cleveland. I have had to travel a lot for work over the years and was impressed by the dining options available and the general togetherness of the community there. Again winters...bad...
But on the flipside, their street maintenance was amazing. It was snowing almost all the time during the winter, but the road were always clear.