cajun seasoning is what I normally use. Just sprinkle on and throw on the george foreman (BTW if you dont have one, get one, they rock, only takes a couple minutes to cook a 10 oz chicken breast)
You can find low fat itallian dressing and marinate them. That is really tasty.
MRS dash garlic and herb rocks too. I do add just a tiny bit of salt with mine though, it really brings out the flavor.