I'm generally in a hurry when bathing, so I'm more of a shower person than a bath person, and reading while bathing is just right out.
On the other hand, I can readily imagine putting my iLiad into a ziplock to float around on the lake.
And I do use my ebook reader while exercising on the treadmill-- I find this much easier than reading a paper book.
For what it's worth, Mike Elgan, the Computerworld author of “Why e-books are bound to fail,” responded positively to this blog post.