I have approx 1000 unread ebooks, and suspect the truth for me is a combo of all the above. I enjoy collecting too; hate to pass up a deal on a good book; mixed with 'the grass will be greener' when I retire and have lots of reading time. But as Charles says, we shouldn't count on tomorrow. Luckily, the hoarding part is fun right now
Plus - you never have to dust ebooks.