Hmm, I must say that I haven't really thought about it, and now that I do, well... I don't really remember it all that well.
Let's see...
The Ace rescue arc and the pirates vs marines was cool. CP9 was also interesting. It's called CP9, right? Hahaha...
Hmm, what else? Oh yeah, the time when Luffy had to fight Usopp over the Going Merry. That was some epic stuff. Their journey as a whole is truly incredible, yeh? So many crazy adventures... hahaha...