I'll have to pick Krispy Kreme, because I've never had Dunkin Donuts, or I don't remember having their donuts before. Though I hear their radio advertisements often at work.
Though personally Krispy Kreme donuts aren't my favorite anyway, they're too rich. Now there is a locally family owned donut shop in town that is amazingly good. Which segues to the next question...
Donuts from a locally owned mom and pop shop or donuts from a larger franchise?