I grew up loving the old Transformers cartoon (even shed a few tears when Optimus died in the first animated movie—LOL). Given that the action figure was quite pricey for my parents at the time, I ended up owning only the cheapest of the lot. Nonetheless, I still have a fondness for the franchise and am excited about the upcoming Transformers 3 (Dark of the Moon) movie, which I heard features Unicron!
The vid below is some piece of magnificent, menacing music, often called "Unicron's Theme." Enjoy!