Get a 2-nd PC with 2 disks, one for OS/programs and a second disk for data. Connect them and synchronize your data. In a domain you can have that done automatically on booting or before shutting down.
This may not be the most common setup for a mere hobbyist, but this is how I did it:
In our situation we have 2 servers at physically quite different locations, connected through a VPN for daily backup, our own mail relay servers, our own domain and a number of PC’s and notebooks (around 8) connected either wired or wireless, running under 2003 Server Enterprise and Exchange Server 2007 with full synchronization of off line files, disk mapping, GFI and Symantec protection etc. and all of the individual PC’s and notebooks have their own slip streamed DVD with their own user profiles, software and settings. I realize this is not the typical setup for a mere hobbyist, but with the help of my son I am quite happy with our setup.