Sony Reader Pocket Edition PRS-350SC (silver)

Pros: E Ink screen, ePub support, compact size, battery life, dictionary, memory.

Cons: Arguably, the Sony price premium (but only $30 over a Kindle is worth every penny for ePub support).

Summary: I have been reading on hand held devices for over 10 years now; from my first monochrome Palm III, to a color Sony Clie, an Asus netbook and now to a dedicated ebook reader. I am a casual reader, usually finishing a book every few weeks. I bought the predecessor to this model, the Sony PRS300, over the Kindle for one major reason, ePub support. I don't collect books, so why would I want to buy them all the time when I can borrow them from the library? The Sony lets you read ebooks from the library, the Kindle does not. If I need or want to buy books, I am not tied exclusively to Amazon. Until Amazon adds ePub support, I wouldn't touch the Kindle.
The reason I chose a dedicated reader over an iPad type device is simple. The screen. If you want to read books, choose a device with an E Ink display, not a computer screen like the iPad. There is no comparison. Reading from an E Ink display is like reading from a printed page. Reading from an iPad (or other tablet with a back lit LCD screen) is like reading from a computer screen. It can produce eye strain and simply doesn't work well outdoors due to glare.
The lack of Wi-Fi is of no concern to me. I don't update content every day or even every week. I borrow or buy a few books, load them via my PC and I'm good for a month or two.
The features I missed from the previous device are now there; glare-free touch screen and built in dictionary. The 5" screen is big enough and the size is great for throwing in a jacket pocket. It's a very comfortable size to hold. I found the Nook to be quite bulky. The keyboard on the Kindle makes it bigger than it needs to be.
Also, by way of comparison, I bought the Sony Daily Edition because I thought I could use a bigger screen. It's really only necessary for periodicals and the previous generation Sony touch screens were quite glare prone. The touch screen glare problem has been fixed and I am more than happy with the PRS-350.
In my opinion, this is the best option for a pure book reader on the market today.