Ive been muting commercials for years.
they are usually at ahigher volume than the rest of the program.
better yet I prefer to tape movies (foreign films from the Independent film channel) or showcase and just fastforward the commercials.

sure you have to have 50 channels to find one decent thing on, but I wouldnt dismiss tv entirely, there are informative documentaries, frontline, passionate eye,etc as well as science shows, like Nova which are well made. I wouldnt waste time on trash tv such as game shows or reality stuff, but then you could say the same about reading - theres trash to read as well. I limit the time to a couple nights a week, at 2-3 hrs at most.
There is something to be said for time well wasted, I dont always feel like doing something productive after a long day at work.