Marco Arment, developer of Instapaper, writing in an amazingly comprehensive review of current e-readers (including e-ink devices and new low-end tablets), writes

If you’re primarily in the market for an e-reader, get an e-ink device. And if you’re looking for a tablet for apps, games, and videos in addition to reading, unless the iPad’s price is absolutely out of the question forever, I suggest getting the iPad.

And the e-ink winner unsurprisingly is the current Kindle (called the Kindle 4 in the review).

The low-end, non-touch Kindle 4 is actually my favorite e-reader today. It lacks the easier text selection and periodical navigation of the touch readers, and it’s effectively impossible to type on, but neither of those interfere with the most common actions when reading. It’s faster, thinner, and lighter than all of the touch readers, the interface makes the most sense and is the most responsive, and it works best with Instapaper.