Google's eBook strategy is excellent. Google licenses eBooks at prices that rival Amazon and B&N, and the eBooks can be read in browsers, on cell phones, on eReaders from B&N, Sony, and now iRiver, etc., and if and when Amazon enables the Kindle to read ePUB eBooks that employ Adobe Content Server DRM (e.g., eBooks that Google, B&N and Sony sell, and public libraries lend), then Google eBooks will be accessible practically anywhere. Pretty shrewd move on Google's part.
The iRiver device looks pretty good, but as duiker101 points out, the Kindle has the unique 3G advantage.