In need of an anime like One Piece?

Only the people who watch One Piece would understand what I want. One Piece is seriously a unique and one of a kind anime, and I can't find anything like it anywhere.

Sure there's your Naruto's, Dragon Ball's, and Fairy Tail's, but that's not what I want. I want a series that builds up the world that they're based in brilliantly, along with having a huge crew of members with back-stories and goals to die for. I want characters that are so welly brought into the show that I tear up at just the sight of them. I want an overall story that nobody can guess what the outcome will be of it. There needs to be substance and an overarching goal that makes me want to keep watching to the very end. You see what I mean?

Anyone who's watched One Piece all the way to the most current on-going episode will know what I'm talking about. What anime should I watch, or is there really not an anime like One Piece?

The only other thing I've seen that is like One Piece in any way is Berserk. I've read the manga, and it's great.

I've literally watched a boatload of stuff, so just try to recommend me something VERY similar. I would prefer it to be a very long anime also, something that really builds on the story...not this 12 or 26 episode stuff. Yes it can be a manga if it's good enough.

http://myanimelist.net/animelist/djsjr