There are too many to count, but I've been revisiting these videos lately:
Also, this isn't a moment per se, but the introduction of the Supernovas is one of my favorite sequences in the series, it felt like something out of a crime film, which is my favorite genre:
Personally, I'd watch the anime until the end of the Marineford saga (episode 516), then go with the manga because it's at that point that the pacing takes a huge nosedive in terms of speed.
P.S. Don't tell anyone you're catching up, I've seen that people have a nasty collective habit of spoiling some really amazing moments.
Its a shame that Monet ends up dead and no one cares a single bit as the Snow Fruit powers and Monets design is pretty cool. Law straight up killing Vergo and Monet seems stupid to me as he could of used the pair of them as hostages in his blood feud with Doflamingo or at the very least handed them over to Smoker
Username checks outLove One Piece, hate Nami. She is literally the worst.