I am currently running 10.6.8 on a Mac Pro3,1 and have heard of the great speed-up gained by going to an SSD. I would like to upgrade to Mountain Lion and need to know how large of a drive is necessary to install the OS and all my applications (approx. 50GBs). I have several other HDs that I will keep my project files, media, etc., on. Besides the OS itself, and my apps, what else should be on the SSD, and what other files are installed along with the OS that I need to have space for?