RuroKen (obviously), Inuyasha, Bleach, YYH and Yuugiou. Alas, if I had the money I could buy so much more.
When I was a n00b at anime, I actually thought it was better than manga because it was in color and you got to see the characters move. Boy was I wrong. But I guess we all have to learn.
The worst butchery of a manga story I've seen so far has been YuGiOh. I used to love the anime. Then I read the manga and saw how much cool stuff was left out. The manga is actually about the characters and the Sennen items. The Magic and Wizards card game is only a secondary theme in the manga. The anime, on the other hand, is nothing more than a half-hour long commercial for the Duel Monsters card game. XP
I've been reading Blech manga online. People are saying there's a filler arc coming up in the anime. I'm glad I don't have to waste my time on that shit.
RuroKen is definitely my favorite! Mangas here in Brazil are ridiculously overpriced! Seriously... Go figure. So I'm sorry to say that purchasing them is out of the question. So I only get them online, obviously. And thus far I've only read RK and Watsuki's other master work, Buso Renkin. And I must say, Buso Renkin is excellent! I really love it. Though not as much as RK. But even so, its definitely worthy of your time! And the ending I might add, was amazing! Unlike 70% of anime and even manga, it was immensely satisfying! I really hope it gets animated one day!
As for manga vs anime, I as well used to think anime would always be a 1000x better than manga for the same reasons you stated... Meh
So the Yu-Gi-Oh mangas are indeed much better than the anime? Hmmm, I like the anime so I might have to read them soon...
I've read great reviews for Bleech. So I'm looking forward to reading them. And perhaps download a few fansubs soon...