OS X is not really a BSD. True, its userland comes from a mish-mash of NetBSD, FreeBSD, classic big-U Unix, and OpenBSD, in roughly that order, but xnu is not

OS X is not really a BSD. True, its userland comes from a mish-mash of NetBSD, FreeBSD, classic big-U Unix, and OpenBSD, in roughly that order, but xnu is not a BSD kernel, and while it supports many FreeBSD APIs (e.g., kqueue), that's done by reimplementing those APIs in xnu, frequently via gratuitous copy and paste, but definitely not by using a BSD kernel. I mention that not because I want to be pedantic, because there's a huge gap between "OS X is using some BSD components" and "BSD would make a great desktop operating system." The one doesn't imply the other. That said, there is a fairly nice desktop OS, called PC-BSD, you can take a look at, that is FreeBSD with a KDE-based UI. Not my cup of tea, but you can check it out at http://www.pcbsd.org/ http://www.pcbsd.org/