My favorite store listed on Melev's Reef is Exotic Aquatics. The manager there, Mike, has been a great source of information. It's a small store and they don't always have a lot of stock on hand, but they get some great fish in and will special order just about anything. He has a great big plant tank in there that he's changed up every time I drop by.
I'm also a very big fan of The Fish Gallery - every time I've been in they have great stock, and a lot of it. I've picked up most of my plants from there too. They have a great big open topped tank in the middle of the floor stuffed with plants. The folks there are always very friendly and super helpful.
Dallas North Aquarium is a very professional looking shop with a real nice fish room, but every time I've been in there I have a hard time getting service. I've picked up a few plants there, but haven't gotten any fish. They're a little spendy in the livestock department too. I like to drop in every now and then because it is such an upscale place, but it's rare I actually end up spending anything.
I've only been into Plano Pets once, but when I did I picked up three Oto's that have done just fine. They had some good looking plants too. A friend of mine recently setup a 90 gallon plant tank that he stocked completely from Plano Pets. Their prices were pretty reasonable too I thought. When I get my 100 gallon up and going I'll pay them another visit.
The Pet-O-Rama on Frankford/Marsh has a pretty plant tank setup with some discus and angelfish that's worth checking out. They are an all-purpose pet store, but their small fish section looks very well cared for.