What are some mature/serious animes?

I'm looking for some serious/mature animes to watch. I've seen Inu Yasha, Yu Yu Hakusho, Blood+, Claymore, and Cowboy Bebop, and liked those. I've also seen Death Note, Hell Girl, Elfen Lied, and Black Lagoon, and absolutely loved these. I also liked Neon Genesis Evangelion a lot until it got psychological and turned into a mindfuck. I'm currently watching Birdy the Mighty Decode and I'm not sure how I feel about it yet, it's a little too kiddy for me. Every anime I've tried watching lately I feel are just too kiddy. I need something more serious. I have Darker Than Black, Code Geass, Mobile Suit Gundam, Welcome to NHK, and Ghost in Shell on my computer because I'm looking for something good, but I haven't had a chance to watch any of them yet. If anyone could tell me if any of these are good/more serious animes, and if any of you have any suggestions for serious animes please let me know. Thanks.