I recently got a Archos 605 Wifi (30G). I must say, that for reading PDF files, this thing is fantastic. They look just as good as my PC and way clearer that my Sony Reader. I still use my Sony Reade for 'everything else'. But I've moved over several PDF files to the Archos. It's screen is roughly half a page worth (feels a little like holding the reader sidesways to read a PDF) with clear color display. Battery is typical for such a device (2 hours or so).
Of course, I'm still waiting for my ideal inexpensive eReader that can do decent PDF.