Heatwave is one of the leading Autobots in the Transformers franchise, specifically from the Rescue Bots media. Along with Chase, Boulder and Blades, he and his Rescue Force Sigma-17 team were tasked by Optimus Prime to set up operations in the technologically-advanced town of Griffin Rock, working undercover with a familyoflocalemergency-responders. Not at all pleased at first with what he deemed to be a lowly task, Heatwave's gruff demeanour can rub his teammates the wrong way, sometimes. But Heatwave is always ready for action and is able to keep his head cool (heh, get the joke? Because he's a firetruck. Like, fire. Cool.) under pressure.
Steve Blum voices Heatwave in Rescue Bots. Whenever I hear Steve as Heatwave, I just picture him in the recording booth with his arms crossed and head cocked to the side in a very "I [the character] don't want to be here"-attitude. Steve's gravelly voice and constantly-annoyed delivery are great for the character.
In Disaster Dash, David Lodge takes over the role of the grumpy firetruck. David also voices Chase and Dr. Morocco in the title, and does a very good job at differentiating his performances. They may not all sound exactly like the role that he's trying to emulate, but the performances are all different enough to pass for a simple tie-in game. He gets the gruffness of Steve's voice down pretty well, and even manages to make Heatwave seem less grumpy and more heroic.
For the spin-off Rescue Bots series, Paul Guyet volunteers to put out the fire (the...vocal...fire...?). His Heatwave has a similar gravel to Steve's, but is much more toned down and a lot easier on the ears (not to fault Steve, but there's so much gravel in his voice that I feel pain on his behalf), which is a nice touch for the character, as he has seemingly mellowed.
In the end, Paul's getting my vote, with Steve in a close second.