-.- , read the criteria guys.
1. Gurren Lagaan:
Pretty much the best shonen anime out there. Meets all your criteria except maybe strong plot. But gotta say, its worth watching and is very entertaining.
2. D.Gray Man:
If you liked Blue Exorcist, you'll like the original. D.Gray Man is a lot more serious though, and i'm not sure exactly where the anime left off. I personally prefered the manga until the artist got sick. But the enemies are more challenging and the plot is a lot more dark. Lots of twist later though.
3. Code Geass:
If your liked Death Note. Code geass is pretty much the combination of Death Note and Gundam. The plot is very interesting on a by-episode basis, and by the end of the series, the main character has come very very far.
4. Kara No kyoukai:
Although with a female main, its not the "loli/big breasted" main character you see in 99% of anime with the intelligence of a schoolgirl. The plot is the best of any anime i have seen, character developement is high, some romance, and quite serious.
-Eden: Its an Endless Wold
I'd reccommend personally Eden and Dorohedoro, as no other manga are unique like them.
But your more of a shonen person so i doubt it.