There are open source tools for developing on Windows, you know. Not just Visual Studio - there are all kinds of free dev platforms for any language you’d like.
You can use SQL Server, or MySQL or any number of databases.
Freedom for developers is pretty darn nice!
I’d like to see the Exchange Web Services API, and Poweshell. Might not get that in the first relese but we’ll see.
Basically if you are the kind of person who wants to develop for the Microsoft platform, you are probably the kind of person who will use their products to develop on. If you are the kind of person who is going to use Eclipse, you probably are you going to gravitate to Java/PHP/Ruby.