From Han Solo blowing Greedo away in the bar to Leia grabbing a stormtrooper's blaster rifle and covering Luke in the detention area, to Boba Fett's strange looking blaster rifle he shot at Luke on Bespin, blasters are and have always been an integral part of Star Wars. Smugglers use them, armies use them, bounty hunters use them, hell, even most 100 ABY + Jedi use them. They might be clumsy and random, but they're also cheap and devastating.
Let's start off with something simple, an Imperial E-11 blaster carbine.
Short and light, E-11 was made by BlasTech industries during the Empire's 19 year fight with the Rebellion, also known as the Galactic Civil War. You might recognize it. Why? It was only in EVERY SCENE WITH A STORMTROOPER EVER. Yup, remember leia taking Luke's gun and telling to jump in the garbage chute? What was she holding? Remember the Ewok's assault on the power generator on Endor? What were the stormtroopers holding? Up to 50 years after the Empire's fall, you can find references of E-11s being used by private security, bounty hunters, smugglers and even some private armies. All in all, the E-11 was an influential blaster in Star Wars.
Now, how a blaster works, is that it uses a gas (Tibanna gas is the most frequently mentioned, most likely because it was part of what Lando harvested on Bespin), and the gas flows through a series of chambers, until it is eventually superheated into a bolt of ionized protons. Then release the valve and BAM, a glob of superheated electrified gas shoots out and melts your opponent's face off. Why do we still use conventional firearms again?
Another famous blaster is the DL-44, or more commonly known as Han Solo's blaster pistol.
Han Solo's personal DL-44 was illegally modified to shoot hotter gas more frequently, but who'd have expected anything different from Han Solo himself? Other people who carred the DL-44 heavy blaster pistol were Mara Jade, Luke Skywalker's wife, and Rebel anti-armor squads, who used this as a sidearm.
In conclusion, what would Star Wars be without blasters?
For addition specs and descriptions of blasters, refer to the internet.