Rico has just posted an excellent blog about some of the architectural decisions he's taken for Visual Studio 2010 and beyond.

It is well worth a read, not least because the questions and decisions made apply well beyond VS, to the software all of us build. Have you got a memory consumption hot spot? Are your extensibility points appropriate to the ecosystem you live in today, rather than the one you designed for 2-3 (or more) years ago? Are you taking bets today that will see you through to the other side of the economic cycle? Will you be better positioned than your competition when business picks up again?