Try this site.
Strictly OP Anime? Watchop.com is the best one at the moment for me. It gave me a lot of trouble a while back but I'm glad most of those annoying pop ups and ads have gone.
All of One Piece (movies, ovas, specials, episodes) are in this one great torrent series. Has through episode 540. Great quality, well compressed, relatively quick download (for a torrent of that size), and some additional bonus stuff, such as everything being arranged by saga and arc and every episode labeled. Also has the OVA that aired before the original series started.
Part 1: http://thepiratebay.se/torrent/7175730
Part 2: http://thepiratebay.se/torrent/7175738
Part 3: http://thepiratebay.se/torrent/7175749
Part 4: http://thepiratebay.se/torrent/7175750