I just use two external hard drives, one of which I keep here at home and one that I keep at work. Every time I make a backup I exchange them. That way even if some terrible disaster happens to my home, I haven't lost my data.
What software do I use for the backup? None. Or perhaps more properly, just good ol' Finder. I do the equivalent of just dragging my home folder onto the external hard drive. That copies all of my personal stuff there. I don't bother with saving the OS configuration and installed programs. That is easy enough to restore if need be, and not saving them off each time saves lots of time and backup drive space. In the end, it is your personal files (photos, movies, music, budgets, etc.) that you REALLY need to protect.
So, why spend money on anyone's backup software? External drives are so large and so fast these days, there is no need.
Time Machine is a pretty good alternative though, I have to admit. I just don't like the idea of it cranking away when it choses to. I like to be in control of the major tasks my computer does, not have it deciding for me... Call me paranoid.