I love my Trek! I haven't tried the other brands, but I can say that my WSD bike is an amazing fit. Of course, it helps that the LBS spent a lot of time making sure it is a perfect fit. I have no trouble with my seat, though it may have changed from last year (I have a 2009 Madone 5.2 WSD).

For the budget you stated, you may want to try the Trek 2.3 WSD. My good friend has a 2.3 (not WSD as he is a guy) and he LOVES it.