The SPAS-12 from Modern Warfare 2
So much fun hipshotting fools with this thing. If the map was ever a close quarters map like Favela, it was crushtime. Even on some of the bigger maps I'd wreck some unsuspecting people with it.
This is the reason (aside from generally better maps) that I actually keep MW2 installed. Mini Uzi/SPAS-12/Throwing Knife combo - and I don't even really use the Uzi. It doesn't matter which map. Whether it's Vacant or Overgrown, I'm rocking the SPAS 12. MW3/BO's versions are disgusting.
Others in COD - .44 and Raffica (MW2), Semtex (MW2/3), FAD (MW3), Mini Uzi (COD4/MW2), Crossbow and Ballistic Knife (BO/2), PDW (BO2), M1 Garand (that last PING!), PPSh, and Lee Enfield (COD2). Any iron sight bolt action rifle. The Javelin in MW2 if it connects with anyone is pretty fun.
F.E.A.R. - the shotgun is an obvious one but much love to the HV Penetrator and most importantly the
MP50 Repeating Cannon. The latter truly makes the slo mo effect look like pure carnage. I could even fap to its chamber cycling sound. Easily a top 3 weapon for me. Also a shout out to the best grenades of any game.
DOOM - Shotguns.
Rage - Wingstick.
HL2 - Gravity Gun/Rocket Launcher/Crossbow.
Wolfenstein TOB - Bombenschuss.
Resident Evil - Any Shotgun or Magnum. Hence why I never like Claire campaigns. The Red9 (RE4).
Dead Space - Javelin (DS2).
GEARS - Torque Bow.