I was impressed with the Dallas Museum of Art, and the Dallas art scene as a whole. I didn't expect the city to be the spreading ground of creativity that it is.
The DMA is one of the largest and most comprehensive art collections in the country. Admission is free, so there's no reason you shouldn't become antiquated with every exhibit at some point. I was particularly fond of the Ancient American Art section, though these ancient guardians from the Asian were rather impressive - and intimidating. I want one.