i know im pretty late, but ill just post my take on the archos 605 as an ebook reading for future reference (google searches
Reading a PDF file is WAYYYY TOO SLOW. Do Not Believe What Everyone On This Thread Said. It is horrible. No one should have to go through that.
Browsing through the pictures IS REALLLLLLLY FAST. PICTURES LOOK REALLY GOOD. For reading books if you convert them to pictures you can read them VERY well. This is also partly because the archos 605 has a stand. So you can make it stand vertically and then press the buttons with either of your hands to turn the page.
Sorry i dunno about reading stuff like comics. Never tried it. But for someone who wants to watch videos without conversion in suberb quality, and also read books sometimes, the archos 605 will suffice.
Heres a relevant thread on archosfans about how to turn your text files in images: