VMs for SharePoint

It is preferred to develop for SharePoint on a VM running Microsoft Windows Server 2008 R2 as one has to actually install SharePoint in the development environment and SharePoint is heavy. One can install SharePoint at Windows 7, but I get the impression Server 2008 is a better, easier fit. Having the SharePoint environment walled off from everything else you work on is wise. The SharePoint stuff could muck up the environment of everything else.