Ennies Lobby. Some of my favourite moments out of all the manga I've read were there.
Usopp's struggles with self-worth and him being reassured by Sanji with that great and fitting speech "I'll do what you can't do, you...you do what I can't do", when he notices Usopp doubting himself even more and wants him to reassess his worth and purpose on the crew and in general.
Robin's declaration on wanting to live was wonderful too and I always remember Franky's line, "existing isn't a crime". Sanji vs Jyabura, Zoro vs Kaku and obviously Luffy vs Lucci were all great too. Monster Chopper reveal was one of my favourite moments.
I just loved the themes of the members of the crew relying on the others for help and to make up for their own inabilities. From Nami taking over for Sanji due to his chivalry leaving him incapable of harming Kalifa to Sanji saving Usopp from Jyabura and dealing with him to Usopp stopping Robin's capture after Sanji couldn't do anything about it and obviously everyone assuring Robin they'll do anything for her no matter how much the government chases them. I kinda also prefer Enies Lobby's villain cast with Lucci being amazing as a ruthless assassin, Kaku being an enjoyable and likable antagonist, especially with his moments at Galley-La prior, and Jyabura being quite entertaining whilst still dangerous.
Sasuke Retrieval Arc was great and I had very few complaints and it left me satisfied. Neji's fight against Kidomaru, the Kimimaru fight and Naruto vs Sasuke were my favourites from the arc.