Auron, if you like SciFi/Fantasy try
Baen.com. They have all the more popular formats and are DRM free as well as reasonably priced. In fact they have a "free library"so you can sample various authors.
As to the Cybook/Sony/Astak, I agree with Harry. I do not find the Cybook awkward in any way (except that they have not implemented the delete button in software yet). I admit the my Sony is their earliest model - the PRS-500 but the Cybook is, IMO, the best of the three right now. I think the Astak has some real potential though & I do like it. It is my second most favorite.