I am wanting to upgrade my hard drive, and wanted to know what is best. I have a 2.53 GHZ Unibody MacBook Pro 13.3". The main things I am looking for are speed, and I want it to be near silent. Also, what is the difference between SATA 3.0Gb/s and ATA 6, meaning which is better? I would like to get at least 500GB but maybe more.