Here's the shocking truth. No format is perfect for all media on all platforms!
I like reading novels, and I am still not sure how a previous poster managed to use the phrase "chapter books" as an insult! For me, my 505 carries all the novels / chapter books that I can feasibly read at any one time. I tend to buy ePubs, because IMHO Sony do a nice job of formatting them, and thanks to the efforts of people on this forum (the I love Cabbages chap, Kovid and some very helpful 1-2-1 coaching from JSWolf) I reckon I can ship them to another device sans DRM in an emergency. I have a novel in PDF format on my 505 - it looks awful. I don't know whether I should blame Sony, Adobe or me for buying it, but lesson learnt - ePubs work for novels on a 505, I have a 505, I read novels...you get the drift.
I like maps. Detailed maps. Maps that take up more than a screen. I can download a map of all the cycle lanes in London as a PDF, blow it up, crop a section to print, zoom right out to get an overview. Maps on my Mac are fabulous as PDFs - in either Preview or Adobe Reader. I would never dream of putting them on on my 505.
So let's all be friends. Bad news for people who hate ePubs, they are gaining in adoption. Bad news for people who hate people who read chapter books - that's a lot of hate. And really bad news for who hate PDFs - if a publisher insists on you seeing the layout that they envisaged, it's going to be PDFs for some time to come!
Great debate though
amjb