This past spring I bought an Acer Netbook. I bought it for its portability and for the sole purpose to make it an Ubuntu machine. I can't say enough positive things about Ubuntu, a Linux program. No pesky firewalls or anti virus programs and I can read pdf's, djvu documents, and it uses the Open Office program which is similar and in most cases better than the Microsoft Office equivalent. This machine along with a small outboard drive (120 Gigs) will hold my entire survival library which consists of nearly 8,000 books and articles I've saved from the net. I've spent years building up this library. I have a 9 hour battery for the Netbook and a 2 hour pack for backup (its the original which came with the machine). I want to find a good solar charger for this setup as well as my other rechargeable batteries. If you know of a good setup, please let me know.
If you plan on building a digital library I suggest you read this article: http://ronsprimitiveskills.blogspot.com/2009/03/building-digital-library-for-self.html
This is just a suggestion and its how I built my library.