The bad part about eBooks is that they always pile up. They are probably the most non-read books in existence. Or why should I bother reading 16 eBooks on the same topic, when reading a single good one would be the sane solution (the one I'd choose for paper books)?
I certainly agree with you. Often, it's just better to buy a paper book than try to read a little bit here and there. After all, paper books are not that expensive. My personal problem is than I often buy books that I never end up reading, or that I read after years (five, six, or even more). I'm pretty sure I'm not the only one that suffers from this, though.
Actually there are several really good books in this list, also available as paper copies if you want (albeit quite expensive if you go that route. ESL for example is $70+).
But I do agree, a good textbook is well worth the investment over some free poorly written one.