I had to impose serious limitations on myself to narrow this down to even close to 10 films. I almost made it. I could probably come up with 10 movies that everyone should own in ten different genres. Brazil Groundhog Day Office Space UHF Ronin Bladerunner: Final Cut BBC Planet Earth Falling Down Harold and Maude Pleasantville Queen - Rock Montreal Tampopo
Planet Earth is on my wishlist. Feel free to expand on your 10. I need ideas. I already have 700 movies and i'd like to buy stuff on BR that i don't already have, though I will undoubtedly replace a lot of them as well.