"Shakunetsu no Ikari" by Osamu Totsuka & Takeshi Ike (from Dancougar: Super Bestial Machine God)
Sometimes an anime is defined, sound-wise, by something like an OP... And then there's stuff like this, where an anime is defined by a piece of BGM. That little intro is like a tease, making you almost want to skip ahead but you worry you'll miss the real into to the song. Afterwards this song just simply rocks. Sure, it's little more than a simple riff that's repeated ad-nauseum, but like I mentioned with "Destiny girl" from the OPs list sometimes that one riff is enough to keep your attention. In terms of show use this song is sometimes used during the combination sequence of the Dancouga[r] itself, other times you'll hear "Kemono wo Koe, Hito wo Koe", & other times it's used during battle. Regardless of timing, though, this song just screams absolute awesomeness. You want to know how badass this song is? Games in the SRW franchise that feature Dancougar originally used the first OP, "Ai yo Faraway", or the first ED, "Burning Love", but once "Shakunetsu no Ikari" was used in SRW Alpha 3 it afterwards became the absolute only song that represented the series. Screw any sort of song you can sing to, even Banpresto knew that you shouldn't f*** with this song!