We have had SF starships, movies, songs so how about personal SF weapons. My favorites:
Space 1999 stun gun, unusual design.
original Star Trek phaser pistol.
Logan’s Run Sandman pistol, with the cool blue flames out the muzzle.
Xena’s Charkum (sp?)
Star Wars light saber
Not to burst your bubble or anything but Xena’s charkum (sp?) was a real weapon used in India or Pakistan and possibly a few other places. No it didn’t bouce off several objects and return to their hand but it was used in hunting.
I’d have to say that my favorite SF weapon would have to be the phaser from the original Star Trek or that monofilimant wire from Johnny Mnuemonic.
Marc
Xena’s circular throwing thingy = chakram (I think).
The Gun from the original (book) version of Logan’s Run was pretty damn cool - it looked the same as a Peacemaker revolver, but carried six rounds, each with a different function - I remember armour piercing, explosive, anaesthetic gas, and the “homer” round they used to kill the runners, which tracked anything with a human body temperature and, on hitting, burned out its nervous system. IIRC, even without any of the specialised rounds, the power pack in the gun’s handle could fire a burst of heat that could cremate people.
Best weapon, though, has to go to the Xeelee “starbreaker” gravity-wave laser in Stephen Baxter’s stories. Somewhere in “Vacuum Diagrams”, there’s the story where one shot from one of these destabilises the bad guys’ home star and sends them fleeing in terror. Not bad for a handgun!
I like Worf’s (ST:TNG Klingon) crescent choppy thingie, which I believe was called a bat-leth.
Definitely, without question, Reason from Neal Stephenson’s Snow Crash.
Reason was a Gatling-type (or maybe closer to a Vulcan) personal railgun that worked off a portable fission reactor.
They cut a fishing trawler in half with it initially, then the main character , Hiro Protaganist, uses it to blast a hole in the side of the USS Enterprise, converted to a personal luxury yacht by a fundamentalist televangelist.
Amazing rate of fire and penetration. Not much use against soft targets, though, as it tends to render them into red mists without much stopping force.
Larry Niven also had some interesting ideas in the Ringworld series-Slaver stasis fields, monatomic disintegrators, etc…
For sentimental reasons, I’d have to have a chrysknife from Dune, but you’ve got to know that it’s easy to make folks listen to Reason.
On the other hand, on of Keith Laumer;s Bolo tanks would be a handy platform from which to fight…
Don’t know if he invented it, but Asimov often featured “Needle Guns” which shot, I believe, exploding needles.
Also the “neuronic whip.” It was like a “force field” whip which directly affected nerves. It really, really hurt.
The weapon from Krull. That was pretty funky.
In a long-ago role-playing game, my character had a sonic stunner made by StunCo. Not much range, not many shots, but pretty accurate. Most people it hit, fell down.
StunCo - Shoot first, ask questions later.
I bagsie Adamantium retractable claws!!!
Oh, and a Larry Niven Tasp would be cool, tho’ I’d probably have an enormous battery bill 
Ok, so it’s pretty old but I really liked the Arc Saber from the game Recoil. Zaps multiple enemies with cool blue lightning. You don’t even have to aim.
Aside from that, I also fancy Darth Maul’s double-sided lightsaber and that hand laser thingy from Space 1999.
From Dan Simmons: a FORCE Deathwand. You point it it someone, they die. Simple as that.
I’m kinda fond of Doc Smith’s space axes. Who needs one of those wussified blasters when you have a dureum battle axe and powered battle armor?
Dammit, Alessan, you beat me by about twenty minutes.
Nothing says casual elegance like reducing all of your enemy’s synapses to slag. The hellwhips were pretty cool, too.
Since the deathwand’s already been taken, I’ll take a FORCE: Multi-Purpose Assault Rifle. Those suckers can fire thousands of flechettes, slugs, energy pulses, grenades, hyper-g lozenges, and all sorts of other fun stuff.
I see Niven has already been mentioned, but False_God skipped the coolest one: the soft weapon from, well, “The Soft Weapon”. It was a tnuctipun spy’s weapon, sealed in a stasis field, and it could shapechange into several different weapons–all of them impressive. I remember a setting for a plasma jet that could be used as a thruster, at least one projectile setting, an energy absorber that would shield against energy weapons (including kzinti sonic stunners), and the cream of the crop–a total mass conversion beam (whatever you shot was converted into energy). That last setting was for use from orbit–a pistol that could wipe out cities.
It was powered by mass-conversion, and had a internal computer capable of assimilating a new language within a few hours. It was also capable of determining that it was in unfriendly hands, and tricking the kzinti into destroying themselves.
The lightsaber. Truely an elegant weapon from a more civilized age.
Well, if computer and video games are fine, then I’ll just get dibs on the good ol’ fashioned BFG from Doom. Sure, it’s got a bit of a warmup time, but one hit will take down anything in this dimension, and you don’t have to be too fussy with the aim…
Anything that Yama built in Roger Zelazny’s “Lord of Light”, including the wand Agni, the Lord of Fire, carried. As I recall, it was attached to armor covering half of his body so he wouldn’t turn himself into a charred skeleton.
Also for those familiar with the Amber series, the archaic Chaos dueling weapons Merlin and Jurt used. I think one of them was called a trisp. They were sort of like combination daggers/claws/lasers and could be adjusted so they would give only shallow, deep, or fatal wounds.
Actually, Maeglin, I was going to mention that too. Unfortunately, thousgh, I don’t have the Cantos with me at work, and mentioning it without listing all of its features would have been somewhat lame. My memory isn’t what it used to be.
Preacher’s Voice of God.
He looks at you and says,“DIE.”
And you just die…like that.
OR…He could say “GO FUCK YOURSELF.”
And you pull down your pants, rip your dick off, and shove it up your ass.
The Voice of God…infinitely more powerful than the Force or DUNE Witch Voice.