The idea that Japanese animation is so much better because it's more lenient in what can be shown (because cartoon boobs and showing a lot of graphic violence equals quality), that it's much more original (so many of the storylines are cliche, pillaged, or unoriginal, it's just that the better stuff tends to be imported), that the animation is better (uh, stills? Framerate? Hello?), many of these things that the otaku deify don't really hold up to scrutiny. One thing I will give is that Japanese animation tends to have much more room for more mature and adult theme, as well as social commentary. That, however, does not mean that American animation is bad (I dare anyone who saw the Batman animated series, one of the great animated series, to say it was bad).
Family Guy, Simpsons, Batman, Gargoyles, and many, many others, ignoring these in the discussion is akin to put your fingers in your ears and going "la la la la, I'm not listening" (I wouldn't be surprised if some of them did it too).
There's room for discussion on the merits of different animation from different countries. One thing the discussion doesn't need though is unfounded fanboy hate.
P.S. After seeing a number of American cartoons that are styled after Japanese animation (Totally Spies is just one god-awful example of it), I'm thankful that most animation studios still use their own styles and techniques.