I think the gals here are on the right track. I say, if it fits, and something about it just excites you (color, shape, lines), go with it. Don't limit yourself to WSD, unless you are truly petite. Plenty of regular ("men's") bikes come in small sizes. I find that the selection of regular (non-WSD) stuff is much greater than that for WSD, and tends to be of higher quality. I think WSD is only a good value if you really need a very small size.

Also, I have had some good luck with good deals on bikes on eBay and mtbr.com classifieds.