My sweetie and I went to A Touch of Grace on Monday. This store has a very large collection of furniture for sale - that takes up most of the square footage. All of the furniture seems to be in good condition - no ragged upholstery or broken doors... or smell, which I've caught in a couple of used furniture places. The furniture is fairly solidly middle class - overstuffed couches, entertainment centers and the like. It would be a good place to furnish a first apartment if you're on a strict budget. They also have TVs which actually work.
In addition to furniture, this thrift store has a nice large book section, with a huge selection of children's books. The books are even semi-categorized, which earns them points with my husband. There's a few clothes, but it would definitely not be worth going there for that. There's a small collection of housewares which are very nice, plus some of the other stuff that you end up having in your house, such as blinds and tools.
This is just down the road from Graceful Buys, which is more clothing/housewares oriented. In addition to these, there is a furniture resale shop that is called "Kiss It Good Buy", which is worth going to for the "what were they thinking" factor of some of the furniture, if nothing else. These two stores are at the end of the Downtown Grapevine shopping district, so you could make a day of it.