Icon doesn't mean "first" look... and it doesn't mean "accomplished goal"... and it doesn't mean your favorite look... it means the appearance of the character that everyone generally associates with the character.
At one time it seemed like pretty much everyone thought of Luke dueling Vader on Bespin... therefore, the Bespin fatigues were Luke's most iconic outfit.
For example, on the Fox lot, the side of a sound stage has a massive painting of Luke in Bespin fatigues crossing sabers with Vader. Generally, when they show a single clip of Luke, it is him approaching Vader for their showdown. The "I am your Father" moment is so iconic. The two best films of the OT culminate in that moment. It is the resonating 'shock' that Star Wars makers are still trying to match -- i.e. Han getting killed.
Therefore, I think the Bespin fatigues are his most 'iconic' outfit.
At one time it seemed like pretty much everyone thought of Luke dueling Vader on Bespin... therefore, the Bespin fatigues were Luke's most iconic outfit.
For example, on the Fox lot, the side of a sound stage has a massive painting of Luke in Bespin fatigues crossing sabers with Vader. Generally, when they show a single clip of Luke, it is him approaching Vader for their showdown. The "I am your Father" moment is so iconic. The two best films of the OT culminate in that moment. It is the resonating 'shock' that Star Wars makers are still trying to match -- i.e. Han getting killed.
Therefore, I think the Bespin fatigues are his most 'iconic' outfit.