Boy, the things you learn when you have a kid and start watching morning cartoons.
First off, they're not as obnoxious as I would have imagined. I really enjoy Bob the Builder, though part of my enjoyment is marveling at the stop animation. Sid the Science Kid is also fun, and it tickles me how they throw in some pop-culture humor in there for the adults once in a while. And then there are the old stand-bys like Sesame Street, which remains sublimely silly.
One interesting thing I picked up on yesterday morning upon watching Maya & Miguel for the first time was how one of the child characters (Andy Arlington) doesn't have a whole right arm. This was striking to me, as I had seen handicapped people in cartoons before (usually in wheelchairs), but never an amputee. I really respected the show for that sort of inclusion, and I'm glad little C.C. is being exposed to that.
Of course, Maya & Miguel also features main characters who speak Spanish, and are therefore subverting American English. Damn PBS and it's quest to teach our children about tolerance and respect for people of all walks of life!