Originally Posted by Billi
The ebook readers that allow the most options in regard to formats used, fonts, customization are Pocketbook 622 and Onyx Boox i62HD and Bookeen Odyssee. Like the Kindle they all have a dedicated subforum here where you can get further information.
I agree - all excellent devices. Their only downside is that because they aren't subsidised by being associated with a bookseller, they are somewhat more expensive than the heavily subsidised devices from Amazon, B&N, and Kobo. I owned devices from all of Pocketbook, Onyx, and Bookeen in the past and been very pleased with them.
I would add that the ability to read many different file formats is overrated. Using Calibre, it's very easy to convert between ePub and Amazon's formats (those are the only ones that matter, from a practical point of view), and the conversion both ways is seamless. So you can buy a Pocketbook and still buy books from Amazon, or buy a Kindle then buy books from Kobo. The choice of bookseller really shouldn't constrain the choice of device.