I started participating in a social experiment by trying to not say "dude" "like" or "hella". My friends and I started doing this because we realized we sounded like idiots saying like, dude, and hella so often. Now we call each other out now when those words slip in. Its quite fun. I didn't realize how often I speak before I think. This whole talking exercise has really made me much more conscious of my speech and the speech of others. By not using "like" I am forced to talk intelligently!
Even more interesting is listening to other people as they say "like". Recently I listened in to a office receptionist as they said like practically every other word. I could hardly stop myself from bustin' up.
Try it out, listen to your speech, find a filler you use most, and take it out of your vocabulary, then listen to others as they say it!