A question

Any thoughts on this would be much appreciated. A resource I'm in love with is Thomson-Gale's Eighteenth-Century Collections Online--digitized images (made from a massive microfilm collection) of almost every book published in English in the eighteenth century. But I can't read multi-hundred-page theological treatises or whatever on screen, which has led to a lot of massive printing jobs that are not a sensible use of paper. What are the options for a hand-held reading device? Has anybody tried the Sony Reader, particularly for PDF files of the kind I'm talking about? Are there other options? I'm skeptical about electronic readers for light reading--it has to do with the cost of content, not the cost of the original device, I just can't imagine paying so much money for digital files of books I could, you know, get from the library or pick up used or whatever--but I would pay several hundred dollars for a really convenient way of dealing with this kind of electronic file so that I could read it comfortably.