I don't know, Pink Floyd covers aside, I never really liked Hipgnosis. Even then, my favourite Floyd cover is 'Animals', which was originally a Roger Waters idea executed by Hipgnosis. Storm Thorgerson recently came up with this for a 7" by repeat offenders Biffy Clyro:

Which caused no end of merriment when it arrived in the shop.
The Scorpions, of course, managed a cover that was even worse than 'Animal Magnetism', but I'm not going to be damn fool enough to post it here. The album was called 'Virgin Killer' and both the original and replacement covers are on the Wikipedia entry.