Today I discovered there are third-party SSD's which are cheaper, and smaller than Apple's. I also found out they decrease boot time in addition to file transfer time. What I need to make sure of is - can the OS be installed on an EXTERNAL drive and booted from it if I just leave it plugged in all the time? Or for startup does it have to be inside the computer? Also, I was thinking of a cheap 30GB or so to transfer photos from each individual project while I'm working on it to reap the speed at the moment, then archive to my 1TB HD. I can wait all night to store them for good but I just want to get the benefit at the time that I want to work on them and also so that it doesn't drain the battery of my camera for the initial backup. Does this make sense and would it be worth in the neighborhood of $50-80?