I use it everyday in my job and it provides a wealth of opportunities for our business, but tonight I found one more reason to love it at home. After my last project of removing the hard disk from my MythTV frontend, I still have an issue of migrating my backend system to CentOS. A blind upgrade is a scary prospect on a fully working system so I'm loathe to just stick the disk in and see what happens.
The free virtualization software from Sun. In no time at all I had installed that old noisy 10GB hard disk into an external USB case, attached it to my PC, and allocated the drive to the virtual machine and booted to the CentOS installation DVD. With this I can test an upgrade from Fedora Core 6 to CentOS 5 on a system that is reasonably similar to my backend and see if there are any major issues. If something goes horribly wrong, no harm done and none of this testing required any hardware on my part other than the drive itself.
I'll report back later on how the upgrade goes...