@Steve > Welcome and congrats on the purchase!
The first thing you should do is update it to the 1.60 firmware, announced just a couple of days ago. Obviously, if you're familiar with rekordbox at all, you've got a leg-up in the game. If not, you'll want to import your music and have rekordbox analyse it all for you. If you haven't done that yet and want to use your Traktor cue / memory points to save the time / effort of redoing them all, consider purchasing Rekord Buddy; it's a 3rd-party application (by one of our forum friends, Didier) - only catch is there's no Windows version.
Regarding USB drives, your mileage will vary regarding the performance and reliability of USB devices; we recommend testing them at home before using them for performance. Some drives have low-quality memory management chipsets which can have issues with Pioneer players. Best to purchase high-performance drives and test them thoroughly. Unfortunately we don't keep a list of compatible devices as there are simply too many drives on the market to do so.
Let us know if you have any other questions.