I loved the old Mac. It was the most user friendly system out there -- and as a musician I needed just this. I also cut my teeth on unix (specifically SysV), so when OS X came out, it was the best of both worlds.
Give me a unix based system that I can do my research and gives me low latency with an interface that I don't have to think about, and I'll be happy. I can't stand Microsoft at all...it doesn't do userfriendly well, and the nerd side of it sucks (even if you put the GNU tools on it...I don't even know if these exist anymore, but it was the only way I could get by dealing with NT back in the day).