I went through Parris Island with a M14. I went to Camp Geiger at Camp lejune for ITR with a M1-Garand. Did BITS with a M14. Some of my senior officers and SNCO's had served in the Pacific and Korea. In Vietnam they finally forced me to get an M16 half way through my 2d tour attached to the 3rdMarDiv.
No doubt for me, of the USA's 2nd WW II weapons it would be the M1 Garand, with a 1917 or 1911 on the hip. It ain't exotic, or fancy, just works, and no one ever questioned the "stopping" power of the 30-06, or for that matter the 30-06 short or 7.62 NATO. My ten years in Corps I was qualified as expert with the rifle and 9 years expert with the pistol (my first year I was not given the opportunity to shoot the Pistol for Qual). I did not like the M16, and still don't, I still prefer the M14.
As for those folks that want a belt fed machine gun, enjoy. The first thing we used to tell the FNG's is if you want to be popular and have all the bad guys shooting at you and have any heavy weapons the enemy may have with them being aimed at you, be on the gun or be near the gun when it opens up. No thank you. The gun is a bullet magnet. God Bless our gunners.
AS for the question on the table, to reiterate: M1 Garand and Sidearm.
Go figure.
Fred