Any city / town in Germany. Big cities will have stalls every day from 22nd/23rd November till the 23rd of December; and every village will have their local ones for those weekends. Gluhwein will be flowing
Cologne has nice ones, although it's possibly a bit too crowded, Frankfurt is okay, Munich is cool, Dresden is good (has the biggest Stollen - Christmas cake) and Nurnburg is nice. They're all "quaint" though. But it's (the Gluhwein that is) the best thing to keep you going on a cold winters night.
Personally, prefer the local village ones now, but only cause I've been here for eons.