Just saw your other thread on
booting four different OSes on one box...
If you would like to take the time to learn / practice with FreeBSD I think you'll find that it is an oustanding OS -- even as a desktop. To go that route, start reading the
handbook. There, among many other things, you'll learn how to boot to single-user mode and copy files (as prescribed in that mail archive thread).
If you want to get a unix-like box up and running with as little effort as possible, allow me to suggest PC-BSD or Ubuntu. Try 'em both and see which you prefer.