There are a number of tools in Ubuntu that you can use to backup your Linux system. In Ubuntu 9.10, when you open the Software Center and type "backup" in the search bar, you are presented with a load of choices. To be honest, I do not know which one is the best one. And yes, you can use the command line to run tar, rsync, scp, or whatever your favorite backup program is to use in these situations.
But, I think that the Ubuntu developers should consider selecting the one that they think is the best, and include it as part of the their operating system as an easy to use graphical interface. Possibly they can build upon a open source application or create something that is akin to Apple's Time Machine. The Time Machine program is very powerful in that it allows you to save multiple versions of files, and easily restore them using an intuitive graphical interface.
It seems that everyone is hanging terabyte hard drives on there PCs via USB and backing up files to it these days. These drive are often less then $100 and offer a great way to protect the files on your systems. It is prevalent in the business world as well.
One the strengths of Linux and Apple's OSX is the ease in which you can save off file systems without the snags of having to deal with registry settings in Windows, etc. It could further set Ubuntu apart in the operating system world by introducing an easy to use backup and recovery option by default.