Not so much ex-rental, but I go to garage sales, second hand stores and 'swap meets' and buy a lot of music VHS tapes that will most likely never see DVD release (because my taste in music is so bad, LOL!). The odd thing is, I don't watch them because I no longer have a VCR to play them on! My whole intention for buying them is to convert them to DVD but I never get around to it. I also have plenty of music/movie/porn VHS bought new during the 90's when VHS was king, that I'd love to be able to watch again. I've always loved new audio/video technology, so as soon as DVD appeared, I always bought DVD format where possible - even before I got a DVD player!
With MP3s and 'downloads' taking hold, CDs are going the same way. I am sad about this because CD audio quality is FAR better than MP3 audio quality plus I love having the CD cover/artwork/booklet to look at. I love the packaging of a CD, you just don't get that with MP3. The only benefit I get from MP3/download popularity is that a lot of people are converting their music collection to their iPods and then selling all their old CDs, vinyl and cassettes for cheap, so I always manage to find a lot of great stuff in quite good condition for an absolute bargain! I want to convert my old vinyl and cassettes to WAV but I never get around to it. I won't get rid of my vinyl or cassettes, I just want to listen to them again in CD quality sound.