Yes, I know that this is weird, but I have installed Windows 7 to my development notebook to see how it survives. (Ok, I have a backup XP as well on the machine.)
Generally it works very well, I have not found any major problem with Windows 7, and it seems that the stability has been improved a lot since the pre-beta.
The only problem I have encountered so far is with WCF service applications. If I create a WCF service and host it on the ASP.NET Development server, then all of the WCF requests return an HTTP error:
The remote server returned an unexpected response: (400) Bad Request.
This can even be reproduced with the simplest WCF service that is created for example with the “WCF Service Application” project template.
It is also interesting that the service serves the WSDL request well, it just produces the error when you call a service method. With IIS (after I was able to set it up) the service worked fine.
I have no idea currently what can cause this behavior, but it can be reproduced on other Windows 7 machines as well.
Update: It’s a known security-related issue with Cassini in Windows 7 beta build 7000 and will be fixed in next release. (see http://social.msdn.microsoft.com/Forums/en-US/wcf/thread/123f0d20-a018-48b0-ab92-4aae749f2d5e/)
Thanks to Johan for the update (http://weblogs.asp.net/jdanforth/archive/2009/03/14/bad-request-with-wcf-service-in-cassini-on-windows-7-beta.aspx).