Flamethrower is a move with 90 base power (95 before Gen 6), 100 accuracy, and 15 PP. It's also available as a TM, which can be taught to Pokemon like Nidoking, Weezing, Tyranitar, Flygon, Togekiss, and even Slowbro. That's why I like Flamethrower.
As for Flare Blitz, I'm not a fan of that, because of the recoil. If I use a physical Fire type, I'd rather teach them Fire Punch, Flame Wheel, Blaze Kick, or Fire Fang.