I in principle always prefer ebooks over paper, and when purchasing books will purchase the ebook if it is available. However, I am not interested in going to the effort required for option one. Most of the paper books I read are in the purgatory of being in copyright, but not available as ebooks (and many will likely never be). I actually rarely buy these as I can usually get a copy from my local library soon enough. So I guess option two is closest to my actual behavior. Though often enough option five is true.