I've been upgrading my OS's since OSX Tiger using the "Upgrade" option. So presumably I've accumulated some leftover stuff from previous OS's that may or may not be affecting performance. With Mountain Lion, I'm going to leave my 750GB HDD intact and will instead be installing Mountain Lion on a fresh new 240GB SSD. What are my best options for transferring all my settings over to the new system so that it still feels like mine but without all the accumulated stuff that I don't need? I'll install my applications separately one by one as I need them and I'll do the same with my files, moving over files as I need them. What I want to have on the new OS from the start are my iTunes collection, address book, bookmarks, etc. Can we assemble a comprehensive list of what needs to be ported over and what the best options are for doing so?