I know there have been lots of "Can You Believe Used Record Prices These Days??!" posts and I don't mean this thread to be just another one of those. But rather, I'm interested to hear what are the most surprising, formerly cheap, currently expensive records or categories of records out there? For example, a lot of people cite Rumours as a formerly bargain-bin album that now goes for (relatively) big bucks. What are some others in the same category?