Hey Kev,
I was forced to go to Vista when I got my new laptop. I asked the sales rep what it would cost to upgrade from Vista Home to XP. He tried to convince me that it would not be an upgrade. But when I argued that going from an inferior OS to a supperior one was an upgrade to me, he couldn't find an argument. 
Anyway, he told me it would be $350 to have XP instead of Vista Home. So, I instead spent $150 on Vista Ultimate. In my oppinion, having Vista Home is the second worse thing you can do to a computer. The first is installing AOL. But, I am not an average user. I am a geek that does programming, art and film editing on my system. I have to keep the performance tweaked as best as I can for the work that I do.
All of that being said, the only real recommendation that I have, aside from upgrading to Vista Ultimate, is to turn off the User Access Control and leave it off. It will make installing and running your older applications much easier.
Other than that, I have actually come to like my Vista U' pretty well. Accept for being a resource hog, it works pretty well.
Liam