Having observed my friend's iPad in the hands of innumerable friends, co-workers, children and babies, I have to tell you that apart from a good wipe down every now and again, I really don't see the need for a screen protector. My friend's iPad has taken a TOTAL beating and still looks brand new. The iPad is a pretty tough product by all reports.
I totally see the need for a CASE, but not really so much a screen protector except for cosmetic or paranoid reasons.
one of poster said he got his ipad scratched...without knowing why.