Cool thread!
Main: G6 Commando - Max Payne 3
This category was kind of a toss up for me, hard to pick one assault rifle over another, but the G6 Cammando seems to have a good balance of power, ammo capacity, and accuracy, the latter likely coming from Max Payne 3's stellar mechanics more than anything else.
Side: HE .44 Mag - Resistance 2
The Resistance series' .44 Magnum 6-shot revolver that has a killer secondary feature in which the bullets can be detonated by the user after they're embedded in an enemy.
Melee: Tomahawk - Red Dead Redemption
Hack, slash, throw, a versatile melee weapon with that old west feel.
Special: Zodiac - Ratchet and Clank: Going Commando
I was going to go with the RYNO but then I remembered the Zodiac, which forms a blinding white light and vaporizes everything on the screen... So yeah, I'll go with that.