Lightsaber...
Pros - cuts anything, can be used for defence, quite (compaired to explosives), pretty colours and makes cool sound, street cred.
Cons - need training, limited range, have to be jedi, takes more effort to kill someone, don't actually exist.
Explosives...
Pros - kills a lot, damages structures, remote operation, can be home made cheaply.
Cons - not that acurate or discrete, can't be used for self defence, won't get through security at an airport.
And as for flame throwers:
Pros: toast stuff, novelty value.
Cons: doesnt kill instantly, short range,
Ideal sollution: Gun.
Pros - good range, simple to use, acurate, kills enough, can get scilencer, also some street cred.
Cons - your opponent may have one.
Take your pick.
Personally i prefer a butchers knife, as illustrated below:
Pete.