FreeBSD and Solaris are substantially more challenging for newcomers than is Linux. And, Mandrake and SuSE Linux are easier to deal with than Red Hat or any of the others I've looked at.
(I recently installed Solaris, FreeBSD, Mandrake, SuSE, Red Hat, and Lycoris, and those were my conclusions.)
Mandrake and SuSE are available in retail boxes from places like CompUSA and Best Buy.
For tips on getting started, see my article at
www.basepath.com/linux.