Doesn't much matter, the top speeds of lone mechanical hard drives don't scratch the surface of the available bandwidth with recent connectivity. Even USB 2.0 is slowed by the drive in a sustained transfer.
However eSata is a solid choice, it was designed for hard drives specifically. You're going to get great latency and a top speed that again, doesn't matter.
Sorry but that's completely false (unless I misunderstood what you were saying). Sustained transfers (7200rpm drive) on a USB 2 connection will get you about 20-30mb/s while USB 3 will net you 80-100bm/s on the same drive. Theoretically esata should be a bit faster but the drive will probably be the limiting factor.