Is there a VM offering preconfigured browsers being identical for everybody? Same JavaScript settings, same (VM) screen resolution, same browser size... Make it fixed and use that VM only for browsing...
That would not prevent all types of tracking but it give people using panopticlick-like tracking techniques a few headaches...
The TOR browser bundle is probably the closest thing at the moment, but there probably aren't all that many people using it, at least compared to the Internet population at large.
A virtual machine or USB boot disk that allows nothing to be written to disk, and destroys all the memory contents on shutdown. Oh, and all connections are forcefully proxied through TOR.
That would not prevent all types of tracking but it give people using panopticlick-like tracking techniques a few headaches...