What are the communities to the north, such as Denton, like?
Denton's really nice. But Dallas has grown so much in that direction (well, technically, Lewisville, etc). I grew up in the burbs of Dallas and my brother lives in a great burb - Coppell - but it's pricey. Personally, I could never live in Dallas again - way too much emphasis on money. The traffic is abysmal (and that's from someone who spends a fair amount of time in Chicago traffic).
If you want a super town that is still reasonable, price-wise, look at Tyler, TX. Wonderful town, expanding rapidly so good job growth/potential and in beautiful East Texas. It's also only two hours from Dallas. Plus, it's the rose capital of the world.
Mckinney is another option, about 35 miles north of Dallas. Population getting close to 100,000. Newer town and lots of new homes (small lots).
Denton is west of Mckinney, but also north of dallas about 40 miles. College town with at least 2 large colleges. It is more horse country up there outside of Denton.
Both are nice towns.