I remember, I was at my friends house and he was watching the Sasuke vs Itachi fight. I never watched Naruto before, so I was curious. I immediatly liked Sasuke and Itachis style, Sasuke a little bit more tho. So I liked Sasuke the first time I saw him in the Anime. I grew on him even more once I started watching the Anime and got to know his character.
When Tobi was telling the truth to Sasuke, which was the pinnacle of Itachi's character - I honestly got the chills and I think slightly teared up (hey, I watched it in anime first, which had that sad music and all), which was when Itachi became my all-time favorite NV character.