Any opinions on backup software?

[stevensspam at cox.net]

Hello everyone,

I've found myself looking at the issue of backups again. Currently I have an network drive which my sister and I will manually copy files over to. While this is better than nothing it's clearly not an ideal setup. I've googled backup software and there appears to be a very large selection so I thought I'd ask if anyone in PLUG has suggestions.

To put what I'm looking for in bullet points:
* Ideally supports backup up both Linux and Windows
* Will work with laptops that may not always be on or able to reach the home network (I don't currently have a VPN set up for my home network -- but that's a project for another day)
* Has a straightforward means of copying the backups somewhere offsite (currently thinking of taking an external drive over to our parent's place whenever we visit, but also considering something like Amazon Glacier)