@Chris > In Rekordbox, go to "File" > "Preferences" > "Export" and you will see 2 sections where you can move ways to sort from the Inactive Categories to Active Categories. Just nudge the "Genre" over to the Active Category, and any others you would like. Then you can move them on the list up and down to have the exact order you want.
Here's a video on how to do it with a USB device as well: http://www.youtube.com/watch?v=tOcSkD4oDyo