Universal Installer puts Linux live CDs on USB flash drives -- with persistent storage
The tool's actually been around for a while, but you may not have heard of it -- it's not talked about as much as other options like UNetbootin or Fedora's LiveUSB Creator. Like Fedora's app, Universal Installer can create persistent storage on your flash drive. That means you'll actually have some permanent space to save things like files and preferences -- instead of just having a flash drive clone of your disc image.
A huge number of distributions are supported, including both the 32 and 64-bit versions of Ubuntu/Kubuntu/Xubuntu and sysadmin/technician favorites like Backtrack, GParted, DBAN, Clonezilla, OphCrack, and System Rescue CD.
The Pendrive Linux Universal USB Installer is well worth a download if you've thrown away as many scratched copies of those discs as I have over the years.