Hi Rick, good opening question! I have to admit - I have yet to have an eBook experience I've really enjoyed. Which I find interesting as I spend 8-12 hours a day reading electronic text! I have 3 devices I read with, and I think this is part of the issue. I have an iPhone with a bunch of different readers installed. Of these, Stanza has worked best for me. But it has not been a great experience in general - I doubt I've wanted to read for more than 15 minutes because of the small screen size, both because of general legibility (I finally broke down and got glasses last month!) but also because of how the small screen really doesn't handle flowing text well.
Christmas '10 I was given a Sony eReader. I was looking forward to this, and it does have a bigger screen than the iPhone, but at 7" it still doesn't feel like a great experience and I have found myself similarly bailing after 15 minutes or so of reading.
Finally, I read on ym Mac laptop. I read both ePubs (using a number of readers but also the Firefox plugin ePub Reader, which I do like), PDFs and of course just through the web browser. So far, honestly, the ones that have worked best are PDFs where someone has paid attention to the font and layout, and web-browsers using the Readability bookmarklet.
I do think some other platforms have dealt with the general readability issue better - lots of folks seem to love their kindles, and the few times I've used various tablets, the larger screen size and crisper graphics have made a big difference. I think part of the issue too is that I haven't availed myself of too many of the additional features that eBooks offer - I am not a big note taker and so the annotation and note features are often lost on me, and I don't commute so lots of the mobility advantages aren't as big a deal for me.
In terms of favourite experiences reading an eBook, right now the book/experience I am enjoying the most is Kevin Kelly's "What Technology Wants." I am just reading it as a PDF on my laptop, but someone really paid attention to the page and font design, and it is a joy to read, plus an amazingly thought provoking book.
How about others? Anyone else out there have experiences trying a few different platforms before finding one that worked for them? Or anyone else finding that some of the new affordances of eBooks really tipped the scales for them?
Cheers, Scott