I had the most noticable results using crest night effects. You paint a gel onto your teeth before going to sleep. It did strip away the tea stains I tend to get, and brightened my teeth up a bit. The only part I did not like was waking up and having to scrape the gel off my teeth (and the corners of my mouth, and the pillow, etc).
My dentist told me that to get the "movie star white" look you really have to go in for the professional treatments.