A lot of the whitening things on the market are pretty much gimmicks -- whitening listerine, whitening toothpaste, etc. These things are not going to make any noticeable difference and if they did it would literally take years to happen. Crest Whitestrips do work but again it is going to take weeks at a minimum for any noticeable or remotely significant difference in color. Porcelain veneers are the best option for "movie-star" white teeth but are very expensive at the same time and still somewhat invasive as far the work to put them in. The best at-home method of whitening that I know of is to pick up some opalescence online (I've always used the 35% but I guess if you have really sensitive teeth you might want to try one of the lower concentrations), and have your dentist make you a custom set of trays. Pop them in for an hour or so every few days and you will start to notice a difference very quickly. You can buy the thermo-forming trays online (and for substantially cheaper obviously), but in my experience they really don't work as well and it can be painful if the carbamide peroxide sits on you gums rather than your teeth.