The best reader for me is my computer, Desktop or Laptop. I find both much easier to read than any other device or even dead book format. Maybe it's just me, but I don't get distracted when I'm reading unless I want to be distracted (i.e. boring book). I can easily read a book on a PC for a couple of hours, and in some cases I have downloaded a copy off the internet, after having bought the physical book because it's just more convenient to read on a PC.
The problem for me is reading ebooks are the lousy eBook reader software. What I do is decrypt the books and extract the HTML, then read them through the browser. I have a couple of bookmarklets which does some nice formatting to the text. Gives a very nice format with my preferred fonts in my preferred size hence no eyestrain.
If you think about it almost everyone is already doing most of the reading on the PC when browsing the net, and yet they find it difficult to read a book on it. I think this is more of a psychological barrier than a physical barrier. In my mind whenever I read a physical book I try to press Ctrl+F to find stuff and groans when I realize 'yeah it's a deadtree format'.
Only special case for having a printed book is useful is for something like a datasheet where you need to keep referring to a page while having other stuff open in both your monitors. But then this is only due to limited monitor count/space.
But maybe that's just me.