1) Time Machine to a Time Capsule because it's easy, quick to recover from user error, seamless, and fully Apple supported.
2) Archives of the Time Capsule drive to an attached USB drive in case of TM drive or verification failure.
3) Time Machine to a NAS attached drive (non-Apple hardware in another location).
4) Carbon Copy Cloner to a 2.5" drive (my primary machine is a MacBook Pro, so if my internal drive fails I can be up and running quickly with external boot - or if need be, internal installation)
5) Carbon Copy Cloner to a partition on another NAS (local but different vendor).
6) And the missing leg right now is CrashPlan to a remote server (my buddy's desktop is now a laptop and not connected all the time).
Via David Anders