I don't really think The Simpsons is the funniest show on tv anymore, I don't think there are any funny shows on anymore.. Of course, I don't have cable.
The last Simpsons episode that I really liked was in season 8, and the last whole season that I thought was mostly good was season 7. And now they just finished season 14 (which I thought was by far the worst yet).
Lame plots, the same plots over and over again, cop-out endings, too many guest stars who don't really do anything interesting, characters acting out-of-character and losing their uniqueness, good characters disappearing while boring characters that no one likes are focused on more, too much South-Park-style disgusting humor, too many Family-Guy-style ridiculous things happening (not that I don't like those shows, but why is The Simpsons suddenly trying to be just like them), too much singing, too much making fun of itself, too many stupid jokes that make no sense, *rambles on for hours*. It's obviously changed a lot from how it used to be... if you took away all past episodes and the newer ones were the first, I probably wouldn't have ever watched more than one episode.
Just my opinion.