Ranch Market has a good selection of food from China and other East Asian countries. This is where I go for okra and seafood to make gumbo. They've got a large selection of frozen seafood and meat, and a decent selection of fresh. Lots of produce, though some of it seems a bit less than fresh (I just go here for hard to find veggies, like okra). This is definitely a great place to pick up rice, soy sauce, and soy beans for cheaper than at a Western grocery.
The biggest competitor for this place would probably be Lee-Lee's. In my experience, this place wins on price. For those that haven't been to either, this place is stocked primarily with East Asian faire, while Lee-Lee's is focused on East Asia, but has stuff from many other regions of the world.