Go for organic, avoid hydrogenated oils, and make sure the only ingredients are peanuts and oil. No salt or sugar added.
You can easily make your own peanut butter too:
1 Cup Roasted Unsalted Peanuts
1 tbl peanut or vegetable oil
Pour 1/2 C peanuts into blender and chop until most the chunks are gone, then add the oil and blend. Add the rest of the peanuts and blend until smooth. You can add more peanuts or more oil to get the consistency you want.
Yields 1/2 C peanut butter,
store in fridge.
I always make my peanut butter, and it's delicous!
Edit: Oh, and for chunky, just add chopped peanuts once you're done blending, you can add as much or as little as you want