This is, of course, very much a work in progress. There is so much to watch and so little time. Which is why I prefer short(er) series. I don't think I'd continue watching after the first string of filler episodes, which are uniformly terrible when it comes to shounen. The only exception to this has been Dragon Ball Z, which is one of the first (the second, to be precise (its prequel being the very first one)) anime shows I've ever seen, as is probably true for many others growing up in the nineties outside of Japan. The nostalgia factor was too strong, but I eventually had to drop it - after the source manga material ran out, they descended into a self-parody which was too disgusting to swallow. If I ever finish Kai, I'll probably include it here, since it's, as far as I can see, what Z should have been. One third of itself and ends with Cell.
One other thing is the absence of some series that are occasionally classified as shounen, but are in fact not - Death Note is the chief example for such stupidity. I don't remember power-ups, shouting, dramatic battle scenes or themes of friendship and love conquering all and bringing world peace. Also no kids overcoming difficulties and becoming better persons on journeys filled with monster-of-the-week / sinister plot to take over the world dangers as a metaphor for growing up and maturing (or anything else). For me, shounen means those things. Being serialized in a shounen magazine is besides the point. Stuff needs to sell, ya know, and guess what's the largest demographic when it comes to that? Bingo.
Update: Recently, I've decided to add TTGL to that list, and therefore remove it from this one. Though it undeniably has shouneny elements, it sort of stops with that around episode 8 or 9. But even before those, it's probably best to think of it as a parody of the Super Robot subgenre.
1. Yu Yu Hakusho
Best shounen evar? It's younger brother Hunter x Hunter will surely be a contender, though. It's funny that I started watching the new HxH before the old one, and came to know of YYH and its connection to HxH last of all. I wonder how and if that will change my opinion of the original series. I mean, first the remake, now the spiritual predecessor...it's going to have a tough time coming out on top. Especially since I'm told the quality drops somewhat near the end of the series. YYH, on the other hand, suffers no such issues. Yes, the ending is a bit rushed. They probably could have launched a 50 or more episode arc set in the Demon Realm instead of the ~12 episode compression we got, but perhaps it's for the best. What I enjoyed about YYH is what I also like about HxH: even if there is a protagonist, it's really more of a team-based show, the fights are exciting without dragging on for too long, there is no filler (yes, 112 episodes shounen without filler...apparently, it IS possible...), no silly plot devices such as characters "forgetting" all the progress they've been through just so the current crisis could seem even worse, the bad guys get steadily more powerful instead of the DBZ-ish fight the most powerful bad guy in universe, win, then fight the most powerful...oh wait mentality, the characters are likeable, no one feels invincible, it has an interesting story...ah, this is now incoherent. I don't care. I loved it. I'd recommend it especially to the nostalgic DBZ fans who wish DBZ was better. Yes, even better than what they did with Kai. YYH improves upon it greatly in every respect. I'm now genuinely looking forward to watching the original HxH as well.
2. Blue Exorcist
One of the nicest gifts of this year, Blue Exorcist is a conventional shounen series in that it uses almost every shounen cliche I can think of - it, however, does it all with style and class. Mostly. There is a reason it is #2, after all. There were a couple of filler episodes and the ending was 100% visible from outer space, right down to the sappy post-ending outro. I'm not really faulting it for the latter, though.
3. History's Strongest Disciple Kenichi
Though Kenichi isn't greatness, I admit I was addicted. And I enjoyed its 50 episodes, but they were rather formulaic episodes, and the cliches weren't handled as well as in TTGL or BE. Its greatest strength are the characters - the supporting characters, to be precise. There wasn't one I was annoyed with, which is a wonder in itself. And young Kenichi himself is rather interesting for a shounen protagonist - he's normal. In the no-power-ups-or-magic-or-mystical-unexplained-abilities-or-occult-artefacts-and-so-on sense. He's not an alien, or a robot, or a demon, or special in any way. I'd be forced to call him the perfect shounen protagonist had he been allowed to keep his growth level - but the formulaicness prevented that from happening, unfortunately. Oh well. Still a refreshment.
4. Eyeshield 21
http://www.anime-planet.com/users/phnsr/blog/posts/9099 contains what I have to say about it.
Bonus: Since it's boring to always just explain the list, I've decided to include musings about shounen I've tried to watch. I thought about including the list of stuff I refuse to watch and a list of the stuff I want to watch, but typing out the reasons for all that would take too much time.
Dragon Ball Z - As explained above, the last two arcs are beyond salvageable.
D.Gray-man - I've watched only the first episode and it failed to interest me even a little. The fact it's 100+ episodes long didn't help its case, either.
Soul Eater - This one did interest me long enough to see the first three episodes, but based on those, it don't think I'd like it enough to justify spending time watching it. I find its self-conscious slickness and humor to be annoying rather than cool and funny. I also dislike most of the character cast, and there's not much point in continuing in such case.