I was looking for something in the same price range for similar use. I picked up one of the new 2007 Trek 4300's last Saturday. I would recommend it now that I've ridden it some. It's comfortable and light (my first aluminum frame) and really fun to ride. So although I can't speak to the WSD version, I like mine.

As far as size, everyone's right on. I'd go to your local shop and feel them out. When I started researching what size I needed, I read somewhere that I needed something between a 19" and 21" (I'm 6'). But when I got to the shop, I found that the 18" in this model was as tall as I was going to go. So as far as size goes, I'd recommend trying a few on and seeing how they feel.