I'm forced to use Windows 7 at work. I run Linux in virtualbox to get round this limitation. It keeps corporate IT departments happy because they can enforce patching policies and audit software.
Same here. Our network is heavy on MS Active Directory authorization, so really the only way to run Linux at all is to host it on a Windows/Virtualbox VM.
Last time I ran into problems with web filters at work, it was because they had blocked a lot of security-related things on the grounds that they could potentially be useful to hackers. For example, the websites for most popular fuzzers were blocked.