I second the CSW M80's - I was in the market for a relatively inexpensive pair of bookshelves and snagged a new pair off of ebay for 250 bucks. Considering CSW lists them as having a $500 retail value, that aint half bad. They sound great too - nice clean bass and they do go fairly low, down to 40hz for a bookshelf. The highs could be a little more pronounced, but for the price i'm not complaining.

And they're built like a tank too - if you're concerned about styling, these things look great in the maple or mahogany. Theyre also rather big for a bookshelf at 15 pounds each and around 18 inches tall. If you're looking for something smaller, the M60s or M50's, also by CSW, usually run about 100 bucks cheaper, and are almost half the size.