Because it is so clear on Microsoft website which of the four editions includes Remote Desktop functionality.
http://www.microsoft.com/windows/windows-vista/compare-editions/default.aspx
After struggling with this for hours...finally getting it to work...and then enjoying the slow-as-molasses solution that VNC is, I started to think that paying $100 or $200 for Windows and just clicking a few checkboxes to enable Remote Desktop was looking pretty damn good. (And Remote Desktop performance is way better, too.)
Funny you should mention how easy it is to enable Remote Desktop in Windows. I was infuriate that Vista Premium Edition removed Remote Desktop. I was able to hack Vista to allow Remote Desktop connection.
http://www.unet.fi/fransblog/2007/08/30/enable-remote-desktop-connection-on-vista-home-premium/
In the end, I found that it was not any easier to configure Remote Desktop in Vista as compared to Ubuntu. This was one of many reason I decided to remove Vista from two of my personal PCs, and load Ubuntu. This is from a long time Microsoft user, who now actively looks to replace MS software with FOSS solutions.
It is clear that the individual who persecutes a man, his brother, because he is not of the same opinion, is a monster. - Voltaire