What are your eyes 'worth'? A white brightly-illuminated background is Not what eyes were apparently designed to 'read' from - and even though I substitue pastel to break the especially awful white glare, adjust room lights yada yada - there's no question that it is taxing to pre-transistor eye organs.
A book is portable; a bookmark can be anything you like. It's ready - exactly where you left off. Aside from compensating the author for her work - it is also a tactile experience, if you've ever owned a superbly bound example. Then too - the typeface is crisp and above all, not glaring.
Fie on your CRT (or even TFT - though I grant that seems.. a bit better). We have only a few years' experience of these monitors - I wonder at what the after-effects might turn out to be in 20+ years. Seems analogous to the hearing losses experienced now by even the very young - after acid rock and idiotically loud amplifiers, sometimes a few feet from the victims.
Save your sensory apparatus from techno-excess. That's my aim, anyway.
(Same for gun owners too macho to use ear protectors)
Happy reading.
Ashton