I used to use the Windows platform , went from XP and jumped to 7 , but I now solely use my Macbook Pro with Lion. While I cannot print on my Mac, I might just put 7 for a dual-boot with Lion so I can do so .
I moved just because the Mac platform is more suited for the creative software than the Windows platform and for their quality and service.
Unlike some who are Mactards , I don't really care what system people use because it only really is based on your preference but for any recommendations, I would say get a Mac Mini or Macbook Air and dualboot it, because there is hardly any rom hacking software that is on the Mac much less on Lion. But nonetheless, the App Store for it is superb and artists and people who have an iPad/iPod will love this platform since the update is making them more in sync. Besides that, it really has no distinct difference with a slight learning curve .
But for cost , make sure you have geeky friends who can supe up your computer or make dual-booting with a mac.