I use virtual machines to test out new configurations these days before I put them on native hardware. This helps a lot, especially when I hose a system, which I do a lot just because I like to see how things work. I use kvm or qemu with the -curses option for operating systems that provide a textual interface to their installers/prompts, and vboxmanage and vboxsdl from virtualbox in a gnome-terminal for the eye-candy.
