Which port has the fastest data transfer rate?

Short answer: Just use USB 3.0

Long Answer:

Depends what you mean by "port." As an external port, you would probably want to go with USB 3.0. However, if you want the fastest data transfer rate, you can buy an internal SSD and connect it to the motherboard with Serial ATA. Be careful, because many parts on the inside of a computer are very delicate. Hope this helps.