TRIGUN!!!!!!!! Funny and lighthearted at first and gets kick ass as it builds. If you liked Cowboy Bebop, I consider it about on par with this... Though I'm not saying they are the same, they're different in a bunch of ways though. In Cowboy Bebop, almost each episode was self contained. I mean... there were only two or three two parters in that series, right? The characters are all realistic, not 'perfect' anit it had some heavy episodes... Trigun... How to put it? Its been a bit of time. Like I said, a comedy, but it builds. The characters are more unrealistic. Its got a little little bit of mystery, and gets more action as the series progresses. I would reccomend giving it a shot, but the first few episodes may not fully sell it to you right off the bat.
I personally like Jyu-Oh-Sei. The story of a boy and his twin brother who get thrown on a planet of wild plants and criminals. Not finished with it, and it can be cheesy, but it looks like it builds, and I like the artistic style. The world itself, the plants have a lot of detail put into them as well as how the people live in such a place.
Oh, Speed Grapher sounds right up your ally. Its dark, but really cool. It goes a little bit into psychology of what it is a person most desires. The main character, having been a photographer in the vietnam war most desires to kill people with his camera. When he gets this ability and learns that it was his deepest desire, he states it perfectly. How fucked up is that?! .... I actually should really emphasize this one some more. When you see some of the enemies and their deepest desires, or even just some of the random characters that show up once... pretty creepy stuff. I joke about showing it to my kid brother in law and my friends are like, "WHAT? NO! ARE YOU INSANE?!!!" I'm a little surprised that they believed me... I mean... you get the idea.
Mushishi. This one... is surprisingly... surprisingly good. Each episode that I've seen so far is self contained, with the main character going around and helping people who have problems with 'mushi' which are kind of like a primitive sometimes spiritual cross between animal... plant... bug. Or at least thats how I see it. Not every episode ends happilly, and I was originally terrified that they would completely screw up translating the short stories in the manga into an anime. I have to say, the pacing, detail, soundtrack, art... everything about it was done really well. (Though the opening won't be what sells it for you though. The opening doesn't really have that much to do with the anime, just sets the mood.) Very mellow, little action. If I had to guess, this wouldn't be a bad thing to watch with a person you're dating... But not just for that. Even if your alone I would recommend it if you can get into nice slow paced episodes. ... If you like seen Kino's Journey, (which I've only seen two episodes of) I would really, really recommend this.
Tekkonkinkreet. Awesome movie. I had no idea what I was getting into when my friend started showing it to me, it started light, and the art style seemed to support that, but it got really heavy and it was... really really cool.
Ranma 1/2... though by your list, everything sounded a lot more serious than this. Ranma is a bit of an older comedy, but I am rather drawn to it. It was reccommended to me many times and I kept putting it down until I finally read the first volume of the manga... it was cute. (Japanese... I can't stress this enough, if for whatever reason my few words persuaded you to watch this, watch it in Japanese.)
Gintama. A scifi comedy that is completely and utterly out there. Being one of my earlier entries into anime, it broke a lot of barriers and I got a real taste of what anime was like quick. I guess I consider it to be like a slightly more adult kids show. The heroes in an episode may tackle a problem, learn something along the way or end with a nice little speech. It has to do with friendship, whats really important in life... and an entire episode dedicated on the characters trying to eat beef, and the psychological mannerisms on when it is appropriate to reach for it, because they are poor and usually only eat pork rather than the expensive cow meat.
Gunslinger girl is pretty cool. Not far into it, but as far as having little girls become killing machines, I feel that it is treated seriously and looks at the psychological impact of what they do. I was originally led astray by thinking it was going to be completely shallow and stupid... at least look at the art. The art really helps get over that sort of worry when you look at it for the first time.
I've heard good things about darker than black... though I wasn't impressed by the first few episodes I've seen. If I didn't really want to see it I'd have already given up.
But this is all personal taste. Good luck finding stuff you like.
