I'm almost ready to make my move to Ubuntu. Solved the problem of what to do with my data: buy a spanking new HDD, 100Gb of space, and replace the drive. At least this means I'll have a backup, although a rather expensive approach!
So, I'll be able to stick the new drive in, install Ubuntu from scratch, then copy my data back from the old drive.
I'm now shutting down all of my applications. Hopefully I'll see you soon in a bright new Ubuntu install!