Teletubbies are about the only thing Fiona likes on PBS (though she does watch nature shows with me in the evening). Sometimes she'll watch Dragon Tales, but that has to be with my husband because I can't stand one of the voices (the big dumb guy, for lack of better descriptors).
As far as Clifford...those books have been around for at least 15 years and have ALWAYS been heavily marketed by Scholastic...so I don't really consider that one an informercial. I grew up on Clifford books, and was surprised that they'd turned it into an animated series. While I don't like it because the characters don't sound anything like how I'd imagined them, it's no more than my dislike of other movies-from-books in the adult world.
I don't like the mass marketing of the characters either. I wonder what could be done about that? If the studios supported by PBS are the ones responsible for signing those rights away, then a campaign could be started...I'm not sure a startup studio would listen...and then you have the BBC and CBC imports.
I don't really consider much on TV educational. I'd rather my daughter go dig in the dirt, discover scientific principles by playing with playdough, water, and/or sand...or watch bugs and birds and squirrels in the back yard. TV for us is a way for my husband and I to catch a snuggle break with Fia (who is off doing her own thing most of the time) during the day, and because it's fun for us to see her enjoy the show. We like the marketing demon that is the Baby Einstein (hate the pretentious name too) DVD series...but once again, we didn't choose that for its educational value (I find it really funny how they try to spin it off that way though!), but because Fiona saw one at a friends house and really enjoyed it...and it's not violent or flashy or hyper, so we decided that'd be fine to add to her choices of lazy entertainment.
BTW, carrots--Hubby and I LOVE Sagwa, Fiona could care less. Sometimes we watch it while she is building towers with her blocks, cans, and books. How sad is that? ;>