John Kabat-Zinn
Less motivational focus and more self-healing focus. Teaches you take time out for yourself. After I met him and addended a lecture/workshop with him at my university last year, I was so moved I bought ALL his stuff on the spot. (And got them signed, woot!)
Just doing one of the stress-relieving exercises on his CDs makes me feel grounded, peaceful, non-stressed, and happy for taking 20 minutes for me.
Yeah, I sound like a hippy, but it's true.