External for video editing with new Mac Pro

I am one of those awaiting my new Mac Pro to arrive. I guess that We need external for the video stuff for FCPX. That is the software I will be working with. I have never thought about Thunderbolt or USB 3 until now since I have been using my old Mac Pro 1,1 since the beginning. I have been looking on the net but never found anything conclusive. I do not need blistering speed yet so I would be thankful if you could advice me an affordable solution. Is USB 3 a good start or is eSATA enclosures with Thunderbolt connection a better option. Pegasus is not a option at the moment.

Thank you
Makki

USB 3 would be a great start. Good performance, etc.

I personally just set up a Pegagus2 R4 Diskless with 4TB drives. With the latest 15" rMBP maxed out, it screams. I got the P2 for when my Tube arrives, also.

Thank you so much Ben, finally I got answer that eases my mind