Personally, I thought the Gewehr 43 was a pretty interesting design. Sure, it didn't have the punch of an M1, but it was semi-auto. I'm not sure of the round it fired though. Anyone know?
Also, the Sten series was a cool looking gun. Pretty sure magazine was 32 rounds. Sorta like a Tommy gun, IMHO.
As for the best weapon, IMHO, M1 Garand. Good mix of accuracy, punch, and rate of fire.
The weapon the Germans made the most of is, IMHO, the MP40 or Karbiner 98k.
Also, the Soviets had a semi-auto rifle that fired the 7.62 round, can't think of the name though.