Which Expressions?

Ah, stupid me.

There is only one Microsoft Expression Media, the former dumbed-down iView Media is not continued by MS. So, if you are looking for a DAM solution, it's Microsoft Expression Media. The current release version is 1, with a service pack adding to one or two decimal point version numbering. That would be the version you want if you are not of the adventurous type. xMedia v1 is essentially the same as iView MediaPro v3.1.3.

I have no idea if the public beta of xMedia v2 is still available, if it is you'd get a relatively stable, rather fast program with some new features and quirks [e.g. XMP and xMedia v2beta aren't friends]. Only this week I found I could crash the beta consistently by trying to updating folders from the root of an external [Firewire] hard drive. This could be a local problem but I doubt it. I'd still say xMedia v2beta is quite good, the release shouldn't be too far off. If external HDs play a [large] role in your work-flow you might want to wait a few weeks.

As for the other programs in the Expression line I don't quite see what a [wedding] photographer needs, and if so, Adobe's alternatives are still the industry standard. They would be: Dreamweaver, Illustrator and InDesign.