So, I'd like to pull the trigger on a new iMac. My thinking was that I would go with the SSD/2 TB HDD option. I can get all my system files, applications, docs etc on the SSD, and the HDD would be set aside for my iTunes library (currently around 750GB). But I was thinking. I already have a FW800 2TB external drive that I could use for the media, and then simply get the SSD option. I just don't know how much lag would be introduced by using the external firewire option vs an internal HDD. Any thoughts/insight?