Red's Douhnuts in Paducah, KY. Haven't been there in years, but I used to pass through Paducah when I was in school and traveling home for breaks. Fresh, hot and oh so good!
Edit: Our nation's love-affair with chains can be mystifying sometimes. I can deal with chain food when there's no good local place, but don't understand the need to go to a chain when there's a much better local option readily available.
Case in point - I was in New Orleans on my way to Cafe du Monde (beignets!). On my way, I passed a Krispy Kreme - a chain with respectable doughnuts, but nothing close to CdM's beignets. The line at Krispy Kreme was out the door, but I was able to walk right into CdM and get my beignets in minutes. Worked out great for me -- better food in less time -- but it just made no sense....