One more thing: there are plenty of dedicated book readers out there, including Amazon's "Kindle", Barnes and Noble's "Nook" and others. My advice is simple: STAY AWAY FROM THEM.
First, they are pricey. Second, no matter how small or light they are, they are an extra device you have to carry with you. Third, they are designed to be used with DRMed contents. Fourth, the companies making them keep the control of these device and what is on it, not you; in fact, Amazon even removed contents from their Kindle device. Fifth, the hardware on these devices is not always designed to act like a simple memory stick, and some will require you to install proprietary software on your computers, or even use proprietary cables. Sixth, these devices are designed to have you pay for the books you read, which I find morally wrong as I encourage people to share (I don't believe that there is any such thing as "electronic piracy").
It is a much better choice to screw the "suits" and their corporate world and use the many websites which offer "ebooks" in various formats for free such as, for example, e-reading, in the Ukraine, or use any filesharing (The Pirate Bay, Demonoid, The Gutenberg Project, OneBigTorrent, Torrent411, RuTracker, etc.) or file hosting (Rapidshare, Megaupload, Fitbit, Mediafire. etc.) option out there. There are many more options out there and just a little research will find you pretty much anything you want, including banned/censored books which no publisher is willing to print (such as the English text of Professor Ariel Toaff's "Blood Passover" - available here).
I really believe that electronic book readers are a fantastic resource and truly a crucial technology for surviving in a world of zombies.