I love my Kindle for a number of reasons but specifically, for the purpose of this discussion, because of its size (ie easily transportable) and its lack of touch-screen technology (no greasy marks etc). I love the idea of having an iPad, but I certainly wouldn't but one primarily to read on. I'd get it for other multi-media reasons. As an electronic book, it's no contest as far as I'm concerned. The Kindle wins hands down.
Mark Staniforth
author, Fryupdale - free via
http://www.smashwords.com/books/view/22744