This my first post to the forums, but I thought it was an interesting topic and that I'd weigh in.
Personally, I cannot see why an ebook needs to cost more than a paperback. In our experience working on the back-end of eReading.com (which is not yet live), we have learned quite a bit about ebook pricing. The general consensus in the industry seems to be that because ebook saturation is nowhere near that of traditional publishing as yet, this inequality in market share must be made up for by higher prices.
This doesn't make a lot of sense to me. Most books from traditional publishers are still being published as both print and digital editions; so why would that have any impact on the digital side? Digital seems almost like "bonus money", if you will, and that's in a worst-case scenario.