As of last year I run a dual boot Linux/Windows Vista but I only use Windows for a few appliations that I need to run for work. Otherwise, 99% Linux, 1% Windows. I find that Windows is a bloated disaster since Win98 I refuse to pay for crap. I use it a few times and I get viruses -- so I'd say that some of the newer versions of Linux like Ubuntu Koala which is free, can and should start replacing Windows. MAC O/S variants and Linux are very close and I'd suggest using anything before Windows.