There are some specific geographical areas such as Plano, Nort Dallas, M-Streets and Lakewood but the question you want to be asking is what Price Point do you want to target as that will impact what areas you can buy and sell in. University Park and Preston Hollow are both HOT areas but there you are looking at $250 - $400/sf. Not exactly the price for the average buyer.
We have a few in New Orleans...as long as you have the crews, there are some deals here in fast growing commercial and residential areas where there is 2 billion dollars worth of work that broke ground 3 weeks ago in 3 mile radius'...and several like this.
As close to downtown Dallas as possible....up through Whiterock lake to NW Hwy then over to Central Expy, up to 635 over to Inwood and back down to downtown. There was a nice article in the paper today with areas, price increases, sales, etc. I've also got a nice stat sheet I can send you if you'd like more detail.