(a) any method that runs for a long time is not going to get used often enough
(b) removeable media are safer in only one respect - offsite backup. They are also slower, have insufficient capacity, are more expensive and pose problems of long-term readability which negate that advantage.
So I use a second hard disk drive, and two packages, both free, and there are other free clones available if you look.
(1) a disk imager - I use Drive Image 2002 which was free on a magazine CD some while back. With that, I take a compressed image of my c: drive once per month or so, to the second hard drive. By the way, the C: drive only carries the OS and programs. I have a second partition for data.