I tend to side with Juuule, my DD watches certain shows everyday - namely Dora, Backyardigans and Thomas. She also goes off to play very well by herself and when a show finishes she can be heard up in her room or where ever acting it out. Ever had a 3yr old come up to you and sat "Hey Dude, you know where Tikki beach is?"
She has train sets which are not branded but she has named certan engines afer Thomas characters.
And she often speaks Spanish words to us - in the correct context like "open the door - say Abre" "Hurry up daddy, vaminos" all of which has been picked up from Dora. I love this as I studied Spanish at school and like to teach her more words as well.
We dont have TV on all the time and also have garden play weather permitting and put CD's on when drawing, play dough, cooking or just to dance to in princess costumes etc.
And we have pretty much done this since she became active. DS is only 10 weeks, but if DD is watching TV and he is due a nap I will let him lie in his chair with the TV in the background.
DD also has a good DVD collection and is allowed to watch one film a day. In total she probably watches the TV screen about 3.5 hours a day - less if she has pre-school or w go out. I think like everything else, moderation is the key.