I have lots of big fat technical books:

*) A good eReader is essential unless you want to set aside a LARGE area for dust bunnies to collect... I like the Sony Reader line because of the way they handle notes, navigation and indexes - great for technical reading - but I don't work for Sony - 'to each, his own'.

*) I generally buy reference type books that are well indexed, and I rarely, if ever, READ them the way you read a novel. I read the preface and intro and scan the TOC and indexes, so that I know what's there when I need it.

*) I avoid big fat books on narrow specialized topics - IMO these generally turn out to be a waste, because by the time you finish the book, the technology is outdated, or you've moved on to another project, or they spend a lot of time on things that any experienced programmer will discover themselves buy just DOING IT.