Ever since the 'Unmount' option was removed in Nautilus in Ubuntu Lucid, I've hated having to open the Disk Utility just to unmount a drive. And seeing as how it was either find a script that works the same way, or recompile Nautilus all-together, I chose the former. Anyway, so here is a basic script that'll unmount a drive. (Should work with any drive, including a disc drive, usb, flash, external hard drive, whatever.)
Just add to your '~/.gnome2/nautilus-scripts' folder.
Credit goes to kelfro, for his original script, and ubulal, for his help with tweaking it.