sorry for the newbie question, I have searched and seem to be a little more confused because of it. I am an iMac user considering a Macbook Pro for my next computer and have been caught up in all this SSD talk and wanted to clarify some things. I understand the logic behind an SSD for your OS, but does the Macbook Pro only come with the one SSD drive? Everything I can see indicates that is the case, so upgrading to even a 500 GB SSD drive is costly. I also see some articles on the web about converting the optical drive to a HD bay and putting a reg HD there for storage etc and then using the SSD for boots etc. Is this a popular upgrade and if not why not? All the talk on here seems focused on upgrading the SSD. Thanks!