Trader Joes is a mix between a gourmet grocery store and a health food store like Wild Oats. They carry a wide selection of organic products, as well as "regular" products that are little more fancy or obscure than what you'd find at your regular store. Many of their items are under Trader Joe's own product line, and all of them delicious! Because of this, most their products are extremely affordable.. not at all overpriced, and sometimes even less than your grocery store!
TJ's has a great frozen food selection without all the preservatives and extra junk in other products. They have all kinds of crackers, other snacks, nuts, cookies, etc., a lot of which are slightly healthier than similar, namebrand products... no tran fats, more whole grains, etc. They also have a lot of fun desserts to try- frozen cheesecakes, ice cream cakes, etc.
While the store is always expanding their selection, it's not quite one stop shopping... certain items on your grocery list (canned frosting, for instance) won't be there.
But everything they have is great. And you don't have to take my word for it-- they have a guarantee on all their products!!