The best answer for your question is "it depends" - Not being funny, but consider the following:
1) What type of services / applications will you be using?
2) Do you have knowledge and experience with Linux?
3) What version of windows do you currently have?
4) What flavor of Linux would you consider moving to?
5) Does your Linux choice support the applications you need?
If you're on a Windows deployment, and all your software / users are entrenched in, say, Windows XP, then Win7 is a great choice. Just be sure your gear can handle the upgrade...
As said, you can try to do a dual-boot of both Windows and Linux (like what I do), or have one of the OSes installed in a virtual machine. Another option is download a live CD of a Linux flavor you're wanting to try, and see how it works on your current set up. Beyond that, there's really nothing else people can say.