Children: TV Time and behavior effects

When my son was an infant I scoffed at the AAP suggestion that no child under 3 should watch any TV at all.  We let our son watch Baby Einstein videos and as he got older, other children's programming like Sesame Street, Super Why, and Word World.  I felt that because we interacted with him and engaged him with many other activities on a regular basis (one-on-one play, singing, book reading, imaginative play, etc.) that he would be fine.  He is about 3.5 years old now, and I've been paying special attention to his behavior as it relates to television exposure.

What I've noticed is that, no matter what the content, he is more likely to be loud and obnoxious, as well as rude, when he has viewed more television.  We have many days when there is no television/DVD watching of any kind ("No TV Days") and on other days he "watches" 1-3 hours, after which I close the television off again. (I typed "watches" because he is often playing with some other toy while the TV is on.) 

For the most part, he watches only shows that run on PBS - and that means it's all mostly educational and with very little corporate commercial activity.  Occasionally we allow him to watch other things, like the Cars movie (which he became terribly attached to for some time) and even Spongebob Squarepants (trust me, I know the folly there).  His worst behavior follows watching things of the latter nature (yelling, boisterous behavior) but, as I stated before, no matter the content, more television viewing = more rude/boisterous behavior.

I'm curious what others have experienced with their children.  I'm also wondering if this relates to his earlier exposure or if it's just part of his personality being triggered by that type of stimulation (he tends to be a loud kid anyway).

At this point, it's manageable and I'm not excessively worried, just curious.

Lotus Carroll, aka Sarcastic Mom, writes @ i am lotus, reviews @ lotus reviews, and is Contributing Editor of Blissfully Domestic's photography column.