So get an e-book reader or use a netbook. The books are downloadable in PDF format. Netbooks with battery life of 12 hours are available for less than 400 dollars. If you like the paper look the Nook is quiet nice. The reason I suggest all this is because I've never found a better reference than the information available online
I personally like the feel of paper, but with the run time, performance, and cost of modern netbooks it's hard not to consider them as a very good investment to access all the literature available on the Internet easily and conveniently.