To add to my original response. If the Expert is the middle ground betweeen the Comp and Pro (I'm unfortunately not familiar with the Specialized WSD line), I agree that you should go with that. My friends with Ultegra-equipped bikes are all very happy with their performance.

I hope my comment about 105 being adequate for "recreational riders" wasn't taken as a slight. I agree that every cyclist--recreational or competive--is entitled to top-end components if their budget allows. Believe me, my next bike will have Campy Chorus on it if it kills me. I was only trying to assuage any concerns that the OP might have that 105 won't perform adequately for her or that she'll grow disappointed with it. My understanding is that while the shifting with 105 isn't quite as smooth and precise as with DA, it's still a good groupset, especially given the price difference between the Comp and Pro.

That said, the Expert sounds like a great compromise.