excellent question
we all want to know the answer to this. at the mom i think the xbrite high def screen from sony is the 'best'. it all depends what you want to do and how much you want to pay.
i am using a four year old dell 12" screen at 800x600 and that is plenty good enuf for text and internet, but not for movies.
search google and you will find explanations of screen resolutions. few people will need 17" wuxva 1920x1200 resolutions, and many find these screens actually make the text too small to be useful.