http://en.wikipedia.org/wiki/Ghent

"Much of the city's medieval architecture remains intact and is remarkably well preserved and restored. Its center is the largest carfree area in Belgium."

I was there last month, it was pretty nifty.

Bruges is super-touristy, Ghent slightly less so. You should try to check out a non-touristy town as well, that nevertheless has a significant amount of medieval architecture. Examples: http://en.wikipedia.org/wiki/Mechelen, http://en.wikipedia.org/wiki/Leuven

One of my favorite movies :-)