Referring compatibility issues you can of course better use Windows Vista because most of the people are using Vista while it is a home user Operating System. However, Windows Server 2008 has several advantages to Vista. You can view these advantages here! To test whether your applications are compatible with Windows Server 2008, you can try it in a Virtual Machine. You can find a good manual here: blogs.technet.com: Testing Windows Server 2008 using Virtual PC (step-by-step).