Crashplan
Whoa, there, let's backup a bit.
Okay, bad pun.
Seriously, though, backup is something everyone should take very seriously and almost no one does. Ironically, the people who should back up the most diligently, i.e., the non-geeks, are the ones who almost never do so.
Backups are painful to do, take time, space, cosmic energy and are no fun. Until your hard drive crashes and you lose all those photos of grandma on the rollercoaster.
Enter Crashplan.
Important pricing information:
Free, as in no money required. Or, as low as $5 p.m., but read the fine print.
You need:
An internet connection, preferably one that's always on while your computer is on. And a suitable lead time for the first backup - if you have lots of data, it could be running (auto) for several days. A local disk is faster but is not an offsite backup.