The easiest way to do this is to run a bare bones Ubuntu installation on your hard drive, install VirtualBox and set up a virtual Ubuntu machine. Run your virtual machine and set up that installation just like you want it with all the bells and whistles you want. Do all of your working and playing on the virtual computer.
VirtualBox maintains the virtual machine as a large disk image file (.vdi) along with a few other much smaller configuration files. Whenever you want to backup your virtual machine, just shut it down and copy its directory to your backup location. I use a Passport external drive for this purpose.
Right now, there is both a Windows 7 and an Ubuntu 12 virtual machine on that external drive. All of the system updates, programs, personal files, pictures, whatever, get saved in those virtual machines. A backup of this type is very fast, as one big disk image file will transfer much quicker than a bunch of individual files would. Since VirtualBox maintains the files in that format all the time, the virtual machine is always configured to be backed up.
One advantage of that setup is that I can run those virtual machines off the external drive on any computer with VirtualBox installed, so now, instead of lugging my computer all around, I just bring my external drive with both Windows and Ubuntu, install VirtualBox on whatever computer I plan to use (I have all the VirtualBox installation files also on my external hd - they are available for all the main operating systems), and I am ready to go. I can either copy my virtual machine to the computer I am using, or just run it off of the external drive.
If your computer crashes and dies at some point, who cares, you just grab your Ubuntu installation disk, install it on your new or repaired computer, hook up your external drive, install VirtualBox, and copy your virtual machines back on to your computer - problem solved with minimal stress, loss of time, and loss of data. How much data you lose depends on when you last backed up. For myself, I do a new backup whenever I make a major change or add a hard to get program. Just make sure that your virtual machine is operating normally when you do it. You would not want to copy a corrupted machine over a good one.
And no, I don't work for VirtualBox.