IMO, the Glock 17. I'm not saying it is a better overall gun than a CZ, Beretta, HK, etc...
But if I was in Iraq, and was in combat, that is the gun I would want. I would want the fewest parts, with light weight, and the most dependable in the harshest conditions.
But for the average gun owner, I would suggest maybe a CZ, or Beretta, but for actual combat....
Glock