All the people mentioning Kobo favorably in these comments... is the main selling point that the DRM is easily breakable, or is it a superior reader or marketplace in other ways?
It has direct integration with borrowing books from the library.
It has direct integration with Instapaper.
You can drag a file onto the device after mounting it over USB.
You can replace the endpoint for the store with a Calibre Web endpoint to directly sync your books from a personal server.
You can pretty easily modify the device however you see fit.
For me the library integration on the device itself was a major selling point. I have no complaints after switching four years ago!
I find their default interface is also good and can read anything without mayor problems, books, web & comics. My reader Elipsa 2e is also great for taking notes and supports notes in book pages, though that specific model isn't supported by the custom firmware.