I've read most of Naruto through my library, and I like it well enough, but what's been keeping me reading is the fan community and a few awesome fanfictions (notably
crossovers, "Team 8', a few romances, and humor fics) which I wouldn't "get" if I didn't continue reading the story. I haven't seen any of the movies and have skipped a few whole arcs that didn't
interest me much.
If I didn't enjoy the large, multi-faceted Naruto fan community, I probably would not have read as much of it as I have, as there are only a few characters, plot points and arcs that I find interesting from the original manga.
As for Bleach: There are two or three very interesting characters whose arcs I long to see resolved, and other than that, it's lost its appeal to me a long, long time ago.
Fullmetal Alchemist and Kekkaishi are two shonen manga titles that I read because I really love the plot developments and characters overall, and I recommend those two over Bleach and Naruto. Both are complete in Japan and nearly complete in the US, and Fullmetal Alchemist has two excellent (and very different) anime adaptations available in English, too. (Unfortunately, I found the Kekkaishi anime to be sub-par when compared to the manga).