Actually, I use my firebending productively. All my civilians that are conquered are taught basic firebending. This is, of course, to create militant weapons easier and save fuel costs with blowtorches.
My main move is the Cut and Cortalize, which de-limbs a person, then cortalizes their wound immidiately with a fire. Extremely painful. Also, I like doing a controled explosion around my victim, which is sometimes a cup, as I love drinking hot tea while taking over countries.
Probably the most fun I've ever had was throwing gunpowder into my enemy's eyes, then igniting it. Ahhh.... good times, good times.