While Chiang Mai's Rachadamnoen Road Sunday Market is my favorite, I think the Chatuchak Weekend Market is worth a visit for those who don't mind a bit of a challenge in their shopping. Yes, it's huge and hot and aimed mainly at Thais, but the "tacky" description is a rather overly broad smear. With thousands of vendors of course there's plenty of cheap crap available (much of which you can find at marked up prices at the night markets), but I've found lots of nice and unique things including home furnishings, antiques, souvenirs and unique clothing designs. Plus I just have fun there. But Chatuchak is definitely NOT for those who prefer to do their shopping in air-conditioned malls.