User blog comment:Tiredman2/What is your weapon of choice?/@comment-4721065-20120826100544

A FENRIS mech: I don't think I would ever need to kill people in this universe, but the FENRIS's small size, taser and the ability to detect weapons and explosives is just perfect.

If the above is cheating, I would go with whichever ME1 pistol has the lowest recoil: it would be easy to conceal and carry and would never run out of ammo like the guns from later games.