Having used quite a few machine guns over the years, both on the range and in combat (all courtesy, and at the expense of, Uncle Sam), my hands-down choice is the M-2HB .50 caliber machine gun. All the rest are just ammo wasters. The .50 cal is actually very accurate, and you can really reach out and touch someone. It also has a real impact on whoever is on the receiving end. I was particularly fond of the Quad-50 we liberated, err, borrowed, from an ADA unit. We mounted it in the bed of a deuce-and-a-half, and would roll into a hot area and use it to clear a perimeter in the jungle - round and round, everything just splintered and blew up, with trunks and twigs flying through the air. Charlie was always watching, and everything in our general vicinity would be pretty quiet for a few nights after such an arrival. Gave us time to set up a good concertina and Fugas perimeter defense (the Fugas is another story, I had a MSgt working for me who absolutely loved to watch, using a starlight scope, Charlie get about 4-5 on each canister, trying to dig it out for their own use, only to trigger it when the maximum number of bodies were above or very close to it. I just couldn't get him to turn off the Starlight scope first, he fried quite a few of them with the sudden bright flash of light from the erupting flaming naptha). My second choice would have to be a M1919-A4, a very well-built gun, followed by the M-60; however, neither was nearly as reliable as the M-2, and the range and power of the M-2 is far beyond that of the .30 Cal rounds. More modern stuff? Nah, the 5.56mm round is not, in my experience, a good combat caliber, far too light for truly effective use on the enemy. Of course, the machine gun is primarily a psychological weapon, used to keep the enemy's heads down and immobilize them. Of course, both sides have them, and use them for the same purpose. No matter what MG, though, I want somebody else paying for the ammo!