After hosing Grub settings on my main machine, I stumbled onto one of those tools that just blew me away.
Super Grub boot disk is small, quick and easy. You just download and burn it to a CD, boot from the CD, and follow along with the excellently written documentation wiki. It took me less than 10 minutes start to finish to be back up and running, and as a side benefit found a good reference about boot loaders.
