Schopenhauer said it well: buying books would be great if we could also buy the time to read them. So, since we already know that we will never have that time then, maybe, we buy books to satisfy a certain sense of property. In other words, we get some sort of artificial brain sweetener. When I buy a book - I potentially know more.
[Source: Why do we buy books? - AntiMail]
Funny, I was just discussing this with my wife tonight (leaving a bookstore emptyhanded again). I very rarely buy books anymore, technical or otherwise. I find myself looking longingly at the purty book displays, but I've finally learned to be pragmatic about it and realize that I'd never actually read them.
I think the psycological rewards of buying books greatly outweigh the practical ones. Buying a book tells me two things:
1) I am buying this knowledge. If I buy this giant book, I will be an expert.
2) I am buying a fantasy of having the time to read. A single aisle in a bookstore whispers of thousands of hours of uninterupted, directed leisure time.
I do buy fictional books I can't get in unabridged audio, but find that for technical info I've got more than I can handle between my RSS subscriptions, IT Conversations, and DotNetRocks. For random access technical info, it's hard to beat Google, especially when it often points to one of the weblogs I subscribe to (and trust).
I'm reading Cryptonomicon now, though, and enjoying it very much.