Expression Blend is the product that will directly bring designers and developers together.
A dev can put together a UI using Visual Studio and then ship it off to a designer who can then de-uglify it using Blend.
With Blend, a designer can actually load a VS solution file, so the integration is
tight. Then, without mucking up any of the project's logic, the designer can take what is most likely an ugly eyesore and turn it into something beautiful and easy to use.
And, yeah - I'm being a little harsh on devs here, but let's be honest with ourselves... Over the years, devs have been doing everything. While that's fun, it's probably not the best thing for the users. Unless a dev also happens to be a designer (which isn't
terribly common), users might be in danger of firing up some hideous beast of an application, covered with strangely shaped controls that don't line up, are oddly color-coded, and generally confuse more than they enable.
Do I sound bitter? A bit. Sure. But, I've been on the receiving end of a few of those apps, and it's a painful experience.
With Blend in the right hands, devs can focus on logic while designers focus on UI, and users can work without being tortured