Interacting with you is always a better learning tool than a TV or DVD. Don't let the advertisements draw you into pushing your child to be some kind of genius. Being the "smartest" student in the class in elementary school has never seemed to be an ideal situation.
Teaching your child to be independently creative is a better way to go. A child who can put things together, figure out how things interact, look for different ways to do things, etc. will be much more successful. And you won't always hear, "Mommy, I'm bored," as she expects you to entertain her. Those children also expect their teachers to entertain them.