Here is how I have set up my DX1 to use for World of Warcraft. I play a Rogue and a Mage.
I placed my most used keys in the center of the pad for use with my index through pinky fingers. My movement keys are in the center. Directly above the movement keys are my action bar buttons, 1 through 9, -, and = (unlabeled). Directly below the movement keys, from left to right, are my 'assist' (unlabeled), flip camera, and auto-run buttons. Slightly to the left of my movement keys is <tab> (cycle target) and 'follow' (unlabeled) keys.
In the lower-right of the pad, used by my thumb, is <shift> (used in conjunction with my action bar buttons to access the secondary action bar), jump, and attack.
Along the left side of the pad, from top to bottom, are the <esc>, bags, character page, map, quest log, and guild list keys. The two buttons to the immediate right of those are sit/stand and sheath/unsheath weapons (unlabeled).
In the top-right corner is the <print screen> and 'toggle interface' (unlabeled) buttons (for taking screenshots).
I am using 36 keys, so I still have 14 keys to find a use for. I thought about putting the F1-F5 keys along the top (to target group members) if I played a healer, or adding class specific buttons (e.g., for Warrior stances or Druid forms). I cannot express how pleased I am with the DX1.