Hmm lets see, I have quite a list...
Actively following:
-Naruto Shippuden. Consistently worthwhile and true to the manga every week.
-One Piece. How can one not? Still the best currently running shonen.
-Romeo X Juliet: The best show from this season, hands down. Awesome art & animation, and a very well told story that references the original material without being a slave to it. Truly anime-style Shakespeare.
-Claymore: Solid fantasy show, albeit clearly influnced by the fighting genre. The brutal violence and dark atmosphere evokes memories of Berserk.
-Nanoha StrikerS: Nothing spectacular, but this has been decently entertaining. Fate and Nanoha are still considerably more interesting and endearing than their subordinates.
-Code Geass: Possibly the best show from 2006, depending on how they end it--this from someone who simply adores Kanon 2006. LeLouch is one of the best and most tragic characters to come along in a long time. Why isn't it July yet?
-Tales of Symphonia OAV: Very appealing fantasy, the first episode was better than I expected from a game-inspired anime. The opening score was simply enchanting.
Stuff I know I should be watching but haven't yet: Gurren Laggan, Heroic Age, and Toward the Terra. All this new mecha and sci-fi, and I'm slacking off? I am duly ashamed.
Recently stopped:
-Bleach. Not very eager for the necessary evil of the current filler arc.
-Prince of Tennis OAV. Seen most of it, but Ryoma vs. Atobe still isn't out there. The wait, it kills me...
-Negima!? What happened to this show? It was amusing to watch, but got more and more random with every episode once all that Black Rose Baron stuff started. Sometimes it seems to get incoherent and zany for its own sake. Note to the director: It'd be funnier with an actually coherent narrative every episode.
-Death Note: Actually, I stopped this after episode 2. Not a fan of the subject matter. I also don't like narcissistic, insane protagonists.