Most (all) of my PDF's I read on iBooks are actual novels or textbooks. Is there a way to force iBooks to use the generic book cover rather than the first page of the PDF document? I'm tired of trying to find a book I want to read when all I'm seeing for thumbnails are the start of the copyright information...
You could convert them all to ePub using Calibre. Add the ePubs to iTunes and they should sync with iBooks. As not all PDFs are formatted the same, some will show the generic cover while some will show the first page when converted to ePub. You can change the cover art for each book individually in iTunes, by selecting the book > Right click > Get Info > Artwork.