Yesterday I bought 6 domains - 2x PR5, 3x PR4, and 1x PR3.
They were dropped domains, and I paid just the registration fee.
They all have plenty of GOV & EDU links, and both the 5's have lots of newspaper links.
However - I did NOT buy them for the PR! I bought them because PA/DA was great (and hadn't been blasted up), and the TF/CF ratio was awesome - each has trust flow over 20, and in most cases the CF was less than the TF.
To those people who say you can't find good dropped domains - I say; stop whinging, and get to work looking for them.