I used to use screen protectors with all my devices prior to the N900. Invariably, the screen protectors got dirty and scratched and looked horrible (even when I would change to a new screen protector every once in a while), but I was comforted by the thought that the real screen was pristine. When the devices eventually died, I removed the screen protector and, sure enough, the screen was pristine, but I never got to enjoy it.

Starting with the N900 I have not used a screen protector at all. The screen has one or two tiny scratches, but overall it still looks great. And I am happy that I have been able to actually enjoy that nice shiny screen for the duration of my device's life. I say down with screen protectors.