Colleyville is nice, but very expensive. I would check out the Mid-Cities area as someone else said, and North Fort Worth (near Keller) is nice. Also North Richland Hills has some nice areas, and Keller. If you are needing someplace in a good school district, the HEB (Mid-Cities) and Keller ISD are the best. Good luck!
I d suggest the Mid-Cites area, which includes cities such as; North Richland Hills, Richland Hills, Haltom City, Bedford (really nice!), Euless, Colleyville, and Keller (also, really nice!). I d stay out of Dallas if you are looking for something nice . Good luck!
We have friends in Colleyville. I really like visiting there. I d move there if transferred to the region.