Someone asked this question over at the Comics Corral recently and I assume it was the same poster, but I am going to answer it the same way here anyway
And I am going to exceed the 5 issue limit by offering two story arcs instead :
1. G.I. Combat #161-162, a story that culminates in the death of one of the haunted Tank's crew. The first comic book death of an established character that I remember.
2.Our Army At War #256 - 260, fantastic Russ heath artwork with Rock stranded in the Pacific. These issues also frequently feature fantastic USS Stevens stories, including my favorite 'The Sea Is Calm, The Sky Is Bright', by Sam Glanzman.
These are, without question, among my favorites from the era, but you can't go wrong with any of the suggestions above, in particular, OAAW 218, and 244. (thumbs u
Oh and that OFF 155 is great! Just action throughout the whole issue, one of my favorites of the entire OFF run.