I tend to like reading physical books (gasp), but some of these are definitely worth scanning through. The E-Books Directory website as a whole has tons of good stuff on other topics, too.
It's collections like these that make me sorely tempted to purchase the new Kindle when it's released. Imagine having every one of these books in a portable, readable, display.
I prefer paper books also, but I also like having electronic copies for searching for specific information. I wish more publishers included cd-roms with their books.