Kindle 3,
or Bebook Mini/PocketBook 360, depending on your love/hate for the size of the screen (Kindle 3 is a 6" device, the other two are 5" devices). If you're on the go, PB360 could be a great choice because you don't have to get a cover, which is a
must if you use it on a bus or in the subway. So, if you're going to try the Kindle, get a cover with that too