I think that my "support" for NaruSaku was one that started building up, slowly, but surely; piling(sp) itself up until what I have now in my hands. A mountain of pink and orange admiration and support for a couple I realized would sooner or later happen. Just like Sakura's love for Naruto, which is the same reason why she's my third favorite character (first, Naruto; second, Jiraya).
But to be specific, I think the scene that broke the ice and opened up the path was when Naruto henge'd and almost kissed Sakura. After that, my mind started clicking quicker and stronger each NaruSaku moment that passed, until we reach the date of today <3
And yes, I think the strongest NaruSaku moments up until now are, as many would agree, PoaL and KN4. (Gawd, I felt poetic today O__o)