There's a scene from Demolition Man that's always stuck with me. Upon fleeing his incarceration in futuristic Los Angeles, the batshit crazy Simon Phoenix (played by Wesley Snipes) goes hunting for weapons at a nearby museum, stocking up on machine guns and pistols when inspiration strikes. "Wait a minute, this is the future," Phoenix smirks. "Where are all the phaser guns?"
Sadly, the world's militaries have yet to field the futuristic firearms we've always dreamed of, but at least movies and television have attempted to make those dreams a reality. Below, an egregiously non-scientific ranking of fictional futuristic firearms based on capabilities, lethality, and real-world practicality.