Like cameras the best eBook reader is the reader you have with you.
This would be the pocketable Kindle or Nook paperwhite touch screen device. Click or tap for a new device already sold in Eurrope for just 10 Euros ($13)
These are far easier to use than larger devices, even 7 inch tablets, if you do any amount of reading.
Even printed books can be too weighty to read comfortably, such as lying down or in the sun.
The only problem is that each device above favors a different eBook format or library. The Kindle uses the Amazon azw proprietary format. The Nook uses public domain pdf and epub standard formats and libraries.
The Nook makes it easier to organize your libraries, both on the device and on a computer. Books can be categorized on shelves. This is important if you want to keep a large number of books available wherever you are.
Adobe Digital Editions provides a great computer program to keep track of your e-books on shelves on computer. Click or tap for ADE.
Now, if you want access to both the Kindle and the Nook libraries you have a problem.
A simple way to have access to all the major e-books is to have both a Kindle and also a nook reader. This is actually not such a bad option because both readers are very inexpensive.
There is another way if you are not faint of heart.
This is to convert the Nook Simple Touch to a full tablet which will run Kindle books.
If you try to do this and you brick your Nook, it is not my fault, but here is how to do it.
Follow the instructions: Tap or click here.
Be sure to insert your SD card before downloading Dropbox.
Stick to Amazon apps.
Replace the Nook menu with the Nooter menu so that you can switch between the Nook e-reader and the tablet function.
Use the tablet function mainly to access the Kindle library and maybe also only a few other tablet functions such as Gmail, a news reader, and so on.
You will still want a Nexus 7 or equivalent for such uses as dictating a posting to a website such as I am doing as I write this.
Dictated and published from my Nexus 7.