It depends on what kind of material you need to generate the beams to shoot people.  Carrying ammunition is heavy and no good if you have heavy machine guns.  Laser guns that create their own energy without lugging ammo would be great.  They'd be easily deployable and you could have infinite ammunition. 

On the other hand there's nothing cooler than the smell of cordite when the rounds go off.  The smoking barrel of a firearm and that gunsmoke smell just make me feel at home and happy.  And let's not forget the BANGBANGBANG, the sound of the brass casing being ejected, and the thuds of actual bullets hitting things.  Lasers might end up making stinky cooked-pig smells.  Bullet holes smell wonderful.

BLAMBLAMBLAM!  Ratatata-tat-tat-tat-tat!

Oh, and girls making shooting sounds is the cutest thing in the world.

We already have Laser Gun technology. They are just not the Laser Guns that we think of when we play Video Games that have Laser Guns (Halo for example). I believe that Laser Guns do a lot of good, but can be bad if it falls into the wrong hands (Iran, Israel, Russia).

I say that Laser guns are good if used for good. I know currently the United States Military uses Lasers to destroy missiles while they are flight. This is good because those missiles might be aimed at a United States military base, Civilian buildings (like a hospital, school), or heck I should just say it The White House. As of right now we don't have the laser guns that you see in Halo, Gundam, or any Sci-fi show involving Aliens; but I believe at some point we might have lasers that will be like those type of laser guns.

That being said however someone could end up using laser guns for evil. Imagine gaint laser guns that could destroy small buildings in a matter of seconds or massive standing armies using laser guns to slaughter people. I don't want to live in a world where a school, building, and large amounts of people can be slaughter in a matter of seconds (not to mention with laser guns common criminals might end up getting them via The Black Market).

That being said laser guns are a good idea, but like any weapon it depends on who is wielding the weapon.