Marketplace on Oakton has a great selection of produce, dairy, deli, frozen fish and ethnic foods. Their produce is reasonably prices and usually fresh, although I do recommend looking closely at what you buy as with any store. When I go, I check out their selection of frozen fish, as the fresh fish I've tried on a few occasions was only average.
Ethnic foods include Asian, Middle Eastern and Eastern European, with an large selection of each.
They have a large deli with great selections and prices lower than the major stores, but Village Market Place on Oakton has better prices on deli for many items.
Still, we've managed to save money on groceries by buying from them and Village Market Place instead of Jewel and Dominicks.