MAL (Model Airplane Labratory) is unique. They have been in business for over 50 years. They have a mixture of balsa free-flight, model railroad, a smattering of plastic kits on the shelves, and a selection of references. If you can get Ed Seay, Jr to get you in the 'vault', there is an amazing collection of estate sale kits. Some strange items, but you need to get into the back room. I wouldn't really make a special trip out of my way to MAL.
A couple of blocks south of MAL, on Shady Grove Rd, is Wild Bill's Hobbys. Wild Bills is like an old Mom & Pop shop. It is mostly R/C, cars and planes, but there is one aisle of plastic. There are some gems mixed in, but you must search them out.
There are Hobby Towns scattered around the Metroplex. The ones in Plano and Arlington are pretty good for a Hobby Town. North Dallas is so-so. I have not been in the others to judge.
Also scattered around are Hobby Lobbys. If you're in town when there is a 40% newspaper coupon, print one out and go shopping. No guarantees as to what is in stock.
Otherwise, there are no real good hobby shops in the Metroplex. The good ones (Phil's, Hobby Maker, Hobby Annex) have all closed their doors.
Squadron Mail Order has their headquaters in Carrollton, TX. They're only open for shopping one weekend at the end of May, associated with ScaleFest. \
Hobby shops in the Metroplex are a wasteland. We tend to order in.