I haven't used VM, but I adore Parallels. THere is a new Parallels update for Vista as well. (i'm using XP with my macbook, but a friend is using vista with parallels. easy to do).
Here is a great how to complete with photos to use parallels with your macbook. Use the most memory possible to a lot to vista, I regret not giving it more when I first set it up.
http://www.simplehelp.net/2007/02/10...through/#setup
good luck!
tt