I remember when DWF Exposed (www.dfwexposed.com) was just starting out. In the early part of this decade they where in the know on the latest/trendy places to go. The kept a list of Dallas hot Spots here:
http://www.dfwexposed.com/nighthot.html
I don't know how active they still are today or how up-to-date the Dallas Hot Spots page is. Though it may be a good guide on where to go for the "in" places.