I was going to post something funny like a storm-trooper rifle, or a Halo gun with some witty remarks, but then I got lazy.
Get a good AK like a Saiga or Arsenal, OR a good AR like a BCM or Colt, learn the system, have spares, have ammo, practice a lot, get training.
AKs because everywhere else uses them, ARs because we use them, and they're both good common weapons systems.