I'd say that Halo trumps the Death Star in terms of destructive power.
I'd like an Alien Symbiote or the goblin glider from the Spider-man movie. Lightsabre / energy sword weapons are cool (either that or the enchanted katana), the staff weapons (2x4s as Marcus calls them) from Babylon 5, and those hand weapons in Stargate that make that cool buzzing sound (1 blast paralyses, 2 blasts kills, 3 blasts distigrates), the skrills / organic energy blasting weapons from Earth: Final Conflict were sweet, and who could forget the BFG9000 from Doom and the Plasma weaponry in Halo. Dune rocks too. "My name is a killing word."