I recently setup a new mac mini running OS X Lion. I installed Aperture 3 and updated it. I was about to transfer my Aperture 3 import/export, etc presets from another computer running Snow Leopard when I noticed that the ~/Library/ folder in Lion is missing. Aperture 3 presets are stored in “your home folder”/Library/Application Support/Aperture/. After searching the web for answers, it turns out the Library folder is not missing, but is hidden by default. I came across a post on OSX Daily (Check it out!) on how to show or access the Library folder under the “Home” folder. Once the Library folder was unhidden, I just copied the contents of the Aperture folder from the other mac into the Aperture folder in OS X Lion. I did all this transferring with Aperture 3 closed.