|eSATA, USB 3.0 or Thunderbolt. |
-Thunderbolt is the newest, fastest interface. However, motherboards with TB ports are still quite expensive, as are TB storage devices. Plus, unless you're using external SSDs or RAID setups, TB won't give you an advantage over USB or eSATA.
-USB 3.0 is the cheapest solution, as nearly all new computers have 3.0 ports. When it comes to the transfer of large files (HD movies, for example), you won't notice a difference between USB 3.0 and eSATA. My external drive transfers large files at 105MB/s over both interfaces. The drive itself is the bottleneck.
-eSATA will outperform USB 3.0 when it comes to the transfer of small files (a folder containing thousands of 16KB files, for example). There's less system overhead with eSATA as well. Overall, I'd say that eSATA is still the best interface for external drives.
-If you're looking for a laptop, look for one that has a combination eSATA/USB3 port.
mATX Beast | LGA2011 i7-3930K @ 4.2GHz | 16GB quad-channel DDR-1866 | GTX 670
240GB SSD+2TB HDD | Asus Rampage IV Gene | Seasonic X560 | Silverstone TJ08-E