I find Caillou and Dora annoying too. However, my daughter loves them. I don't mind Go Diego Go though, atleast that is some what educational as she learns about animals.
My daughter loves Sesame Street and Dino Train too, but her absolute favourite is Toopy and Binoo.
My son is too young to really care what is on, as are my dck's so she just watches tv when she gets annoyed with the little ones.