Hunter X Hunter was recently re-made in the anime. Although the original anime was insanely well done for the time, this new one is actually pretty good.
(only problem is the series is LONG in anime, short in manga, so they aren't even 1/4 done in the anime yet).
Anyway, I'm recommending the manga. Its got sick art, great narration, and some pretty damn cool plot twist/characters. Its made by the guy who made yu yu hakusho, so thats a plus. Its also got a insanely solid power system which is explained early on and solid throughout the entire manga.
-Kekkaishi is one of those manga thats starts out a bit generic, then about 2-3 volumes in, it changes drastically for the better, after that another 10 volumes or so it ups the stage to a very interesting level. Though this series is a bit dark for your average shonen, it is very well made and has some great art.
Tripeace is one of those manga. It starts off something odd, but becomes incredibly fun pretty quick. The characters are the highlight honestly, even though the art is good. The plot is somewhere along the lines of "eradicate war", and the main character has two characters to maintain for some fun comedy.
Its not really shonen, but the second half(new waves) is. Probably one of the better martial arts anime's out there with a good cast. Martial arts with bone cracking, explosive inducing, and sick ass countache driving action. Its fun, its violent, and its got some really cool art.
-Also try Veritas if you like this.
Also not really shonen, but its pretty close. Some ecchi and such early on but about a couple volumes in its all action. Plot, action, and violence. Its all there and its all beautiful.
-First arc is against oda nobunaga
-Second is against the kings
-Third is against the crimson king.
The epicness of the fights just continually goes up. Online scans suck though, but its got great art if you can pick it up somewhere.