Jolicloud Netbook OS

"At Jolicloud we believe a movement has started. A movement that will change the computer industry forever: a world where computers are inexpensive, where operating systems are free and software is online. This is the world we dreamed of when we first discovered computers and the Internet. And this is why we wanted to build an operating system (OS) around a platform that gives everyone the opportunity to be part of this movement and access a whole new range of possibilities. Jolicloud is an Internet operating system[1]. It combines the two driving forces of the modern computing industry: the open source and the open web. Jolicloud transforms your netbook into a sophisticated web device that taps into the cloud to expand your computing possibilities. The web already hosts a significant part of our lives: mails, photos, videos, and friends are already somewhere online. Jolicloud was built to make the computer and web part of the same experience."

Looks like a pretty simple OS leveraging the most common on-line applications.  Toss in a good off-line media solution and this could be fairly compelling.  It is only in alpha now, so you'll either need to wait a while or request a developer version to get a better look.