I suspect its ENTJ, but I also suspect its a side they don't reveal, ever. My ENTJ friend will occassionally dive deep into these crazy emotions I've never seen from him before, and I think that is often what its like.
ENTJ's are very mellow. But their aggression has more to do with absolute and objective facts being set in place, and enforcement of these things. Its the ESTP's that look like ENTJ's you gotta watch out for (myself being one of them). As I've said to several others before, I'm like a fighter jet with the afterburner on. If I power down, I crash and die (If I power down for too long, it actually feels more like I'm being devoured by scarabs from the inside out). The aggressive ENTJ's tend to have more of an inherent aggression, and not so much a driving energy about them.
ENTJ's do not have the coursing electric pulse that drives ESTP's. This is the energy that makes us "doers."
This song represents that coursing electric pulse of ESTP:
ENTJ music actually seems to be much more calm, more cerebral. More along the lines of INTJ music, as most ENTJ's I meet believe themselves to be INTJ.
My ENTJ expedition guide was big into the band "air." As for more aggressive ENTJ music, I'm not too sure. I'd ask [MENTION=7254]Wind-Up Rex[/MENTION] or [MENTION=857]FDG[/MENTION]