Man, why is everyone hating on Caillou!
Seriously, though, the show I can't stand is Franklin, for a lot of the reasons that people are complaining about Caillou... he's whiny, pouts, grouches, and is a general bad mood in a variety of episodes. Even my four year old doesn't care for him. (Oh, and Barney. I won't even LET my kid watch Barney. EVER.)
My son LOVES Doc McStuffins, watches Mickey Mouse Clubhouse, and enjoys Max and Ruby. (While I get that Ruby's a bit of a fussbudget, and Max pretty much always gets his way in the end, I don't dislike the show.)
My son is (obviously) less crazy about "Sophia the First", and I think he's finally outgrown both Yo Gabba Gabba and Bubble Guppies.
The show I wish there had been more of: "The Upside Down Show"
My son and I still play Action Fingers. :D
Oh, shows for the olderish kids:
I do NOT hate Phineas and Ferb. My four year old can watch it, which is good enough for me.
I DO dislike Spongebob. I ESPECIALLY dislike "Regular Show". Every once in a while I'll catch out a shout-out reference, but the incessant failure to develop anything but "heh heh-heh heh-heh-heh" style comedy just doesn't do it for me.