I am upgrading to a new mac and want to pick the right ext HD for a) Time Machine b) external HD for more space c) what to put in the old macbook I am giving to my parents who need NOTHING but Firefox I have the following HDs at my disposal: 1) Old black Macbook's current internal HD (I upgraded 1 yr ago)- 320 GB Western Digital- only 160GB is being used. 2) External 120 GB USB HD in a tiny enclosure - (this is the original installed Black Macbook HD- Toshiba) so it is 4 years old. 3) Current Time Machine HD- 250 GB Seagate ST325082 in a BIG paperback sized enclosure. This is probably 4 years old. 4) a relatively new Seagate 500GB FreeAgent GoFlex ext HD in a tiny enclosure Can people advise me on what HD I should put in the old Macbook for the parents, what I should use for Time Machine with the new computer, and do I need another HD for more storage? Is it a mistake to put the original Toshiba HD back in the macbook because it is 4 years old? It really is all my parents need. My new mac is a 13 MBA with 256SSD. I will likely only have 150GB on it to be honest. thanks!