Honestly, I have been using my Zaurus C1000 without, yes, you heard correct , without a screen protector, and I have had no problems.
Apart from the occasional finger marks, which I just rub away and polish on my shirt front occasionally, there is no blemish on the screen.
I mean, such a bright and clear screen as the Zaurus, should not be wasted being covered with screen protectors
(ducking, from the stones thrown my way)