I just got my new Nexus One phone, and the first thing I did was skin it to protect the screen, something  I should have done with my last phone.  I've written about personalizing your cell phone or iPod with a vinyl skin before, but if you're looking for protection, you can't do better than TechSkin by Skinomi.  It's a clear, thermoplastic urethane film – the toughest of
its class. The film’s “self healing”
technology makes it immune to scratches and virtually indestructible.  It protects your devices while still allowing them to be docked, and it also resists fingerprints and streaks much better than unprotected glass.  It doesn't interfere with the operation of multi-touch screens.  The one downside: For proper adhesion and installation on your device, the device must remain shut off for 12-24 hours.  Think you can manage? If not, order it before you get your next shiny new electronic toy.  Priced from about $12-30, depending on the device, and shipped free to the US or Canada.