I am in the market to replace my aging 2006 iMac. The machine has been great and tremendously reliable but it is time. I am going to be getting a 15 inch MBPR and a thunderbolt display but am concerned as to how to manage moving from a 1tb HD to a 512g or 768g HD. I currently have 800+ gig on my iMac with another 1tb used on a drobo. The Drobo has performed well and kept my data secure but it is also reaching its lifespan as the USB 2.0 is no longer practical for some applications. I use the drobo to store my iTunes library but that is pretty much it. I tried to move video there to edit and it was of course too slow. I am enticed by the pricing of the 2 and 3tb drives available now, but also nervous to have all my data on a single drive. I have looked at the pegasus, but it is a substantial investment. I would like to keep my MBPR as uncluttered as possible moving most libraries over to my external drive, but want my data to be safe. Can I use Time Machine to back up my MBPR and an external drive at the same time? Sorry for all the questions, I am excited to make the switch, I just want to make sure it can do what I need it to do. Thanks!