I have shoulder pain from a nerve infection, due to a dental operation... I used to not be bothered by my laptop's weight, but the Eee has been a godsend through this trying period...

BTW: my laptop is about 4-5 pounds, plus folders, magazines, external drive, adaptor, papers, CDs, etcetera... my laptop bag weighs about 15-20 pounds.
(that's no exaggeration... I used to weight-lift, so I can tell)

I've cleaned it since then, since a friend is using it... now it weighs about 5-7 pounds.

But still, the Eee plus accessories weighs a lot less, and is very easy to carry or stash away when you're on the road.

But the question about eyestrain... it's pertinent... it's okay for a while, but if you're on for hours, it becomes an issue.