Captain Morgan arc
Buggy the Clown arc
Captain Kuro arc
Whiskey Peak arc
Little Garden arc
Drum Island arc
Davy Back Fight arc
Water 7 arc
Enies Lobby arc
Post-Enies Lobby arc
Thriller Bark arc
Sabaody Archipelago arc
Amazon Lily arc
Impel Down arc
Other (Please specifiy)
Those are all more Sagas than arcs. An arc is a smaller part of a saga, like Jaya arc inside the Skypiea Saga, or the Baratie arc inside the East Blue saga. But, the "CP9 Saga", or as I prefer to say, the World Government Saga was my fav, just for Post-Enies Lobby arc and Enies Lobby arc.
My favorite Saga so far is Baroque Works, but my favorite arc is Thrillerbark. So, since you said arc, I voted other.
I love Baroque Works, It gets my vote, but I also like Thriller Bark.
I like the skypiea...
But not the luffy vs. enel though....
I like the royal rumble part.... ^ ^
I didn't really like Skypiea very much. I liked it at first, but then it started getting on my nerves with all that tension and everybody fighting everybody and the God-Enel-is-a-bastard-that-wants-to-destroy-this-island-but-everybody-is-too-afraid-to-even-speak-of-him thing. And Luffy vs Enel was cool, but I've seen better fights. I just liked it 'cuz Luffy really put his brains to work in that fight and didn't win just 'cause he's rubber.
I voted east blue, because of all the backstories that we learned about, and the variety of enemies that were shown, especially good after usopp appears
Had to be Baroque for me, since i think this was the longest and most character developing of them all. and skypeia i thaught was a little boring..
CP9 Saga is my favourite, technically because of the Enies lobby arc due to it having some of its fights being the type of fighting that I am used to seeing when it comes to battles in many of the anime/manga series that I had seen in my lifetime, not to mention that I am a very big fan of fictional martial arts.
Baroque works would be my favourite saga.
CP9 comes a close second.
technically one of the longest arc
you really got to know and get used to vivi
east blue is 2nd because that was the making of the straw hats we know today and plus an original concept before the whole who's got the strongest df power and such
Saga: East Blue, no doubt. CP9 is not that far behind but the East Blue saga is the best reading there is in this world, or at least close to it.
Arc: Thriller Bark. Brooke is my new number one favourite manga character, and the arc itself is one of the coolest yet, so it's gotta be TB.
My favourite arc is now Thriller Bark arc. There is so many action with funny scenes.. i just love it =) and i hope Brook will join too. But i like the Enies Lobby arc too, because everybody showed some art of a new technique.
I liked the Enies Lobby arc since it was a crucial "step-stone" of the SH crew.. It powered them up a lot, made their bonds stronger and even showed to what extent they will to go even only for one nakama. Not to mention the post-enies-lobby arc was also nice.. =D