Best External USB Drive Set-up for WD TV Live to Share over Network

My Equipment:

WD TV Live wired to Airport Extreme Base Station wireless to Macbook Pro

I have had very few problems sharing files from my macbook pro to the WD TV Live as a Network Share. I have also had success using Playback streaming server software on my mac to access as a media server.

Finally, I even got an external USB drive attached to the Aiport Extremem Base Station shared as network attached storage.

However, in the end, I really like accessing the media files directly from an attached USB drive. I like the performance, browsing and how the thumbnail features work on an attached drive.

Instead of sharing files from my computer, I want to copy them to the WD TV Live’s attached USB. I have the WD TV shared to my mac, and I can see and copy files. But it’s extremely slow. 100 times slower than copying to the same USB drive attached to the airport extreme base station. So my network is fine. Instead of copying a file with a constant rate, it peaks to approx 1.3 MB/sec for 3-4 seconds then pauses for 10-15 seconds.

What is the best USB drive to use?

The best file system to used on the USB drive (HFS+ works but is it the best?)

Does the USB port make difference?

Are there any other things to try to improve speed copying files over the network to a USB drive attached to WD TV Live?