This is something I've been thinking to myself: which games have the best shotgun ever? It can be pretty difficult to answer that question since everyone has their own experience with different games and we all have our own taste of what a real boomstick should be.
 
This is my personal pick:   
 

1. Doom: What can I say? the shotgun from the original Doom is the best.  No matter if the enemy is near or far, nothing can stand in the way of this shotgun. It's just so satisfying to pump those shells all around you without having to worry about reloading.
2. The House of The Dead III: Believe it or not, I think HoTD3's shotgun is mind-blasting because it's so fast-paced and powerful. The reload time is really fast and you can shoot hordes of zombies from every angle and distance.
3. Quake II: While the shotgun may not look that strong but once you actually start using it, it immediately becomes your best friend. One blast results to enemies being blown into chunks. I love this shotgun.
4. Left 4 Dead: It's a tough call but between Left 4 Dead 1 and 2, I would say that the first Left 4 Dead has the best shotgun. It's range is simply out of this world.
5. Counter-Strike
6. Duke Nukem 3D
7. Resident Evil 4