I am considering the Western Digital Caviar Green 2TB drive as a time machine backup for my Mac Pro. I plan to put it in one of the internal drive bays. I used to have an iMac with an external drive for time machine but just got the Mac Pro an figured why have another USB cable laying around. Plus the internal SATA would be faster. Do most of you guys dedicate one of your drive bays for time machine? Or do you still use an external? I don't need any elaborate setups with RAID or anything. I only have my SSD boot drive and a 1TB drive for media and files. They both total to around 500GB of files to back up. The 2TB should be plenty for room to grow.