For a headless server in a datacentre, most likely, yes. As a desktop OS, not a chance.
For a desktop, Mac all the way. Mac OSX is the most advanced desktop operating system available.
Obviously, for games, I'd be on Windows, but these days most gamers are on consoles, and Microsoft cleverly switched their attention there already.
Linux is best for Netbooks and embedded devices, and as my job is managing Linux servers, I'd have to say it's damned good for servers, too.
My brother uses Mythbuntu to run his HTPC, whereas I use a Mac Mini. The reason for our varied choices? Budget, plain and simple.