Perusing the internet the other day, I came across a list of futuristic weapons that are being developed and tested throughout the world. These weapons range from lasers, to sonic emitters, to microwave guns. Some of these weapons are already in use within various military and police forces. Regarding zombies, I think they could have some very interesting and useful advantages over regular weapons.
Dazzler http://en.wikipedia.org/wiki/Dazzler_(weapon)
The Dazzler is a gun that emits light of a certain wavelength that, when directed towards a human, causes intense discomfort and temporary blindness. This weapon is in use, and has been utilized by the US military on a number of occasions. This weapon could be used to incapacitate zombies and make them much less of a threat by getting rid of one of their only abilities besides walking and biting, and possibly smell. This weapon is designed to only cause temporary blindness, but stronger versions could feasibly be made. In 1995, there was United Nations ban on weapons that could permanently blind. The reasons are obvious; a blindness gun would probably be the most unethical weapon ever created. However, when used against zombies, I'm sure this moral issue would disappear. If made stronger, this weapon could easily blind a whole horde of zombies. One could then get creative and try to utilize the blind zombies in some way, or just waltz around casually and bash their skulls in.
Active Denial System http://en.wikipedia.org/wiki/Active_Denial_System
The Active Denial System is a riot control weapon used by the US military and other institutions prone to riot-like activity such as prisons and embassies. This non-lethal weapon is usually mounted on a vehicle, where it can be aimed where needed. It works similar to a microwave oven; emitting energy in a beam of high-frequency waves. A microwave emits the energy at 2.45 GHz, however the ADS creates a much stronger beam; emitting energy at 95 GHz. When hit by the beam, humans feel an intense sensation of pain and discomfort in about 3 seconds, as they are literally being cooked. These waves only penetrate so far into the skin, however they can cause burns if left active for a longer period of time. This weapon's effects on zombies would depend on how much they could feel pain, and if that would deter them at all. If so, zombies would simply become confused and incapacitated, leaving them open to attack. If zombies didn't care about pain, then you would have slightly cooked zombies eating you. However, like the Dazzler this weapon could potentially be upgraded to a more lethal version if the need arose.
Lightsaber
The other two are actually possible, however who can deny that running around slicing zombies apart with an ever-sharp light sword wouldn't be fun? Lightsabers would be useless fighting against human enemies, because they would shoot you in the face (unless you're a Jedi, and you're not), however zombies are a different story. They would be distracted by the pretty colors, and then left defenseless as you slashed them apart. You could even throw in some pointless spins and flips, because hey, why not?
You might say, "that's stupid, lightsabers aren't real." to which I would say, "neither are zombies."