Well i know of three special weapons in fallout 3, One of them "Sydney's 10mm Ultra SMG" is a smg that does around 60 damage when fully repaired. I got that weapon from Sydney in the quest were you are sent to recover the declaration of independence. My second weapon is "The Terrible Shotgun" i got this one from a evil shopkeeper underground (killing him gives good karma) this shotgun which is essentially a overpowered combat shotgun dishes out 100 damage a blast. My latest special weapon is "The Kneecapper" (does 120 Damage i believe when fully repaired. i got it off Ronald Luaren, and i figured out a way not to get bad karma from killing him! if you have a body guard with you you should be able to do this, simply plant a frag mine on the ground have it detonate the second you put it down. Then Ronald will get up and try to kill you, your body guard will finish him off and you lose no karma.
Are thier any special weapons that i dont have? anyone know of any others?