Notes:
Really though, everything has it's own pros and cons, and what you use is dependant on what you seek to do. In most cases, using Emulation + API replacement (say, KDE and WINE) will offer a nice segway from Windows to Linux.
However, there are times when that just won't cut it, and you need that whole M$ experience (such as Domain administration where the PDC is NT), while you finish migrating to a new environment. In those cases, only running the VM long enough to use the apps you need may be preferable.