Well, Tekken got bad reviews, and you're a big fan of One Piece, so I'd say go for Unlimited Cruise. I think realizze and Rowzone own a copy of Unlimited Cruise, so you can ask them if you've got any questions about it.
EDIT: oops, seems like One Piece gets 46/100 on Metacritic, whereas Tekken 3D gets 64/100. Then again, I suppose the 46 for One Piece might have something to do with the fact that it's really only half of the game.
This post has been edited by Nathan, Wed, March 28th, 2012 at 19:48