Voted charcoal since that is used the most, but would have picked charcoal and wood if that were an option.
To anyone using the evil lighter fluid, invest in a nice chimney starter or if you insist on using that crap, at least make sure your coals are ash gray before adding whatever you cook.
I gave my brother-in-law a nice Weber chimney starter and we showed him how to use it, but he still uses a half bottle of that nasty fluid to start his grill. My sister always complains about being able to taste it, but he still won't stop because that is how his dad taught him. He grilled brats the summer after getting married and they came out solid black and smaller than a hot dog when he was done with them. He said that is how he was shown by his dad, so my dad said he was going to retrain him.