These days, it only takes an increasingly-cheap USB thumb drive and a program like UNetbootin to create a portable Linux desktop you can run on any computer that can boot from a USB port. But check out the list of distributions UNetbootin can download and install—it's huge, and the names don't tell you much about which distro is best for on-the-go computing. Today we're detailing four no-install distributions—Damn Small Linux, Puppy Linux, Xubuntu, and Fedora—and