I'm certainly not upsest by the announcement...DE was always meant to run on a wide range of hardware, and .Net, PocketPC, etc. are just more platforms.
What does concern me is Microsoft's infamous record of adopting technologies and then altering them in a proprietary way (embrace, extend, extinguish). Surely they must see DE in a similar light as Java...a platform that runs on top of any OS and makes that OS inconsequential...and we all know the legal battles Sun faced. If the press release does signal a major partnership, it is noteworthy because DE may be the largest completely external technology Microsoft have used in one of their products in a long time, maybe since Spry Mosaic?! And MS being an early adopter of DE could signal that their own .Net development is far behind schedule.
As long as DE and .Net remain two distinct products, and Amiga doesn't put too much faith in the partnership (if .Net should go down in flames at the hands of the courts, or from public distruct), I wish them luck.
Todd