cpyke wrote:Well plasma cutters today run on electricity (alot of it). So I would assume there is some sort of battery pack (or in the case of Space Marine plasma cannons, a power generator). Also, according to this:
http://wh40k.lexicanum.com/wiki/Plasma_gun#.UZhhu8r1wok
There is a hydrogen cartridge that needs to be replaced.
As far as the zombie apocalypse goes, I'd say a lasgun because it can be recharged by tossing it in the fire in a desperate situation. And since most zombies won't be wearing power armour I'd say it would be powerful enough.
According to my handy dandy primer (that I required to carry at all times) one can recharge lasgun packs in many ways including chucking it in a campfire. This compared to assault rifle tier firepower, lightweight, bayonet, optics, easy use, low recoil... well suffice to say I think that it is the best weapon one could summon in a zombie apocalypse.