What Hank Hill sells to Texans. You see, charcoal doesn't give a clean-burning flame and that can affect the taste of your food. Propane is also more economical and cooks more evenly than charcoal. If you use charcoal--or even mention it--around Hank Hill, you're going to get a lecture.

It also helps, I assume, that Texas is a big petroleum state and manufactures quite a bit of propane which is sold by the big oil companies, so it's a Texan's duty to use it. I guess mesquite is okay too, but best if you throw mesquite chips over a propane grill for flavor (actually, I believe the best way to do this is to put moistened mesquite chips in a foil pouch which you lay on the lava rocks in your propane grill so they don't just burn, but smoke the food nicely).