Eh, that really depends on what kind of computer you have. In Vista if you have the know-how you can disable everything that makes it stupid (the constant "would you like to run this?" and then "are you SURE?"). I'm on Vista Ultimate, with a quad-core, 4 gigs of RAM and an EVGA 8800 graphics card. I have two hard drives, both 500 gigs and on the other one I still have XP Pro SP3, and whenever I switch between the two, Vista runs just as fast as XP, and it looks nicer, and games that support DX 10 look very noticeably better on Vista than they do on XP. Although over the weekend, because I really no longer turn on XP, I'm putting RedHat Linux on the XP drive to help with my schoolwork.
As for the "window 7" I think he's referring to Internet Explorer 7, which he doesn't really need because it says he's running Firefox 3.0 already.
Internet Explorer 7 is a much safer version of Internet Explorer, providing anti-phishing and other modern browser capabilities, including tabs and a download manager. If you don't have it I'd suggest getting it just because it's easier to do stuff on Microsoft websites with IE 7 than it is to do it with IE addons in Firefox.