just watch lain, is pretty much all that you described, no superpowers, superb plot(and confusing as hell) plot and its only 13 episodes long, unlike those 300+ shonen with no goal ni the story. you can also go for evangelion, but unless you can stand screaming traumatized children, don't.

Sorry I was too late to give you a recommendation but good luck with the ones you've chosen.

A few of my faves that you may like:

Death Note
Cowboy BeBop
Peferct Blue
Princess Mononoke
Spirited Away

For jokes:

Full Metal Panic

Full Metal Panic! sounds to fit what you're looking for.
Full Metal Alchemist is also really good, worth a look.
The Melancholy of Haruhi Suzumiya fits what you're looking for as well, it has a superpowered protaganists, but its done very human like, if that makes sense.

Fullmetal Alchemist

It has a great story, and a great overall message (I actually used said message as a point in my senior paper in high school, and got an A- or B+ (whichever) on said paper)

And it has two series. One which deviated from the manga, and one that's sticking to the manga as I type this. the second rendition will be on episode 15 this upcoming Sunday

Yeah, sure, listen to the guy who hated Evangelion to death after watching it for 10 minutes

actually he has some truth to it, eventhough he is exagerating. death notes main weakness is yagami light, he is the worst main character ever, he is clearly the ideal of the author to what a perfect man should be, intelligent, strong, right and good with the ladies, yet those stereotupes ony fit on the shonen driven 15 year olds and death note(and yagami light) is for people who believe themselves to be way intelligent, were as the plot of death note and eveything else in it aren't that inteligent, and since inteligent is what most people say it to be, it fails. it redeems itself by giving us  near and mello, those two are so awesome.

as far as smart and dark anime goes, i'll say lain again.

Ugh, I hated Near and Mello (more Mello than Near), DN in the ending decayed a lot. Still, the first 12 or so eps are masterful, then the rest of the L arc is great.

I loved DN for the strategies and complex plans, I'm a sucker for that, and DN brings them is spades

Death Note and The Melancholy of Haruhi Suzumiya would both probably be of intrest to you, i can highly reccomend both, as i gave them both 10/10.

edit: also, film wise, id reccomend The Girl Who Leapt Through Time, fits some of what you ask for, and imo, is an awesome film.

yes, watch the girl who leapt through time, its really awesome, also in the movies categories check this ones:

akira(the best movie ever)

5 centimeters per second

ghost in the shell

jin-roh

perfect blue

the sky crawlers

the end of evangelion(after you watch the series)

x(movie and anime)

and near/mello are better than L, they were funnier and more aggressive(mello even gave his life and near was willing to die at the yellow box) the author had a really easy time with l, he just had to devise a plan for yagami and then have L deduced it with no evidence as base, just his supositions.