User blog comment:Vanguard13/Pick Your Poison (Ammo, that is)/@comment-3228423-20120809201528

ME: Tungsten and Shredder rounds, cause each one covers half the enemies available and (as far as I know) didn't do less damage against shields.

ME2: Armor Piercing, Warp and Disruptor ammo, cause they covered a majority of enemies (shame that I can only pick one of the former two to keep for missions though). Least favorite was Shredder Ammo because that got nerfed to only unprotected organic health.

ME3: Armor Piercing, which helps out a lot against the stronger enemies and husk forces, though I'm finding Incendiary ammo to be extremely useful now.