If you haven't been there before, it's an excellent place which has everything. You can either order off a menu, or choose it yourself, supermarket style. This means that it's like walking and picking different assortment of seafood, which you have a shopping cart and a guide to help. They give recomendations and advise the several ways/dishes it can be served up.
One of my favourite dish is with the crab and done with a curry paste, excellent.
Also there is two seating areas, 1 huge one where you can see everything going on around you, or a enclosed area, like an up market resturant. (ie Farang area). Choose the main area, which you wont be dissapointed.
Remember to take their business card (for next time), so that you can direct your Thai Taxi driver to the right location, as there are other seafood markets, but not like this one.
Enjoy....