Now that I have finished Code Geass I don't know what to watch. I have the following on my computer waiting to be watched:
Tokyo Majin (which I have been watching with a friend)
Serial Experiments Lain (which I have been watching with a friend)
Peace Maker Kurogane
Hellsing (the original, not the OVA, I've seen the OVA)
Also, I'm partway through watching School Days and Monster online.
So which should I watch next, of these?
The highest recommendation I can give is for Mushishi. I have friends that abhor anything anime/manga or for that matter Japanese related, and they themselves said that Mushishi was a work of art. That it is, to say the least; the music, the animation, the storyline, the voice acting, they all mesh and blend so well that you forget at times you're watching an anime. Wonderful series, even better manga.
Other than that, Tokyo Majin Gakuen Kenpuchō: Tō and its second season, Tō Dai Ni Maku, are wonderful anime, though nothing to spectacular, the artwork, animation, and storyline are great. The music and voice acting are forgettable though not bad by any means. Recommended AFTER you watch Mushishi.
The others are in my eyes merely good at best, but I'm pretty picky when it comes to which anime I consider worth watching all the way through. A big "maybe" would be Outlaw Star, another one of Cartoon Network's anchor shows back in the day, I see it as a nostalgic anime, nothing more. But many people I know who are at least somewhat into anime say they loved it.