What is your favorite weapon on a videogame? Whether it's a melee object or a firearm.

Mine has to be the RYNO V from Ratchet and Clank Future: A Crack in Time. While it has a center barrel that shoots missiles, it has two outer barrels that spray bullets resembling two overlapping miniguns. On top of that, whenever it's fired, it plays the 1812 Overture by Tchaikovsky. It's over-the-top, it's boisterous... it's the ultimate weapon.

There is another one I really like, and it's the Samurai Edge from several Resident Evil games. A custom Beretta M92F created for the S.T.A.R.S. While not as menacing as other weapons, it is able to do more critical damage on the zombies. Deadly on the correct hands.

How about your favorite ones?

The magnum from Resident Evil 3. Awesome sound, extremely powerful and removes zombies heads.

Hookshot cause I can grab things and go to them

BFG 9000

Doooooomed... oh wait.  You mean Doom.  Thanks.  Now you got me thinking about the Wii U and Vita. 

The disco ball!

Adhesive mine in Time Splitter 2:

I was used to do custom match with only this weapon available, so much fun!

Cerebral Bore (it hunts you and sucks your brain juice)

Falcon Talons from Ninja Gaiden 2/Sigma 2.

Agni and Rudra from DMC3.

Double Enforcers from Unreal Tournament series.

*edit*

Shotguns or various representations of shotguns from various games.  On some games you don't even have to be close range for these weapons to be amazing.  Unreal Tournament's Flak Cannon, etc.  They're my favorite weapons types in Uncharted series, Armored Core series, and Army of Two.

A Light Shining In Darkness from Fallout: New Vegas -

M82 Assault Rifle - Killzone