Dan: In my experience, Isohunt is a great, comprehensive search-engine for torrents, but it's not always the best place to find new TV stuff immediately. Try going to
http://www.mininova.org/get/203825 for the OC episode, and
http://www.mininova.org/get/203240 for Lost, and
http://www.eztvefnet.org/ is a great place to go to get uncorrupted TV torrents. Both of the above torrents are working fine for me, and hopefully they'll work for you as well...
Also, NX: The series I'm currently downloading/watching on a weekly basis are Naruto (the non-filler episodes should finally begin soon), Bleach (the filler episodes are just beginning), Shuffle (just ended), One Piece, any and all Gundam series (Gundam Seed Destiny just ended, but I was pleased to be able to get the new MS Igloo movie yesterday), Noein, Monster, Yakitate Japan, Blood +, and Basilisk, and there are a couple other series that I've been downloading but haven't gotten around to watching yet.
Additionally, I've got hard-drives filled with many of the classics (Gundam, Berserk, Lupin, etc... ), as well as a bunch of stuff that I've watched in the past that's not so classic; and an additional sad/nerdy thing concerning my downloading habits is that while my desktops' hard-drive space is filled to the brim with anime series, my poor laptop is also quite ridiculously filled up with volume upon volume upon volume of manga...