H.A.
Crest White Strips Advanced - Professional Effects. Hands down. I've tried Rembrant and the kind with the little blue light... and several others. I get staining from daily coffee and tea drinking and my teeth look amazing after 3 nights, noticeably better after the first use. Plus these don't make my gums feel weird, some of the other OTC made white spots on my gums and other funky stuff. These are like stickers you put on your teeth - easy easy easy. No trays, no tubes. Great results.
http://www.amazon.com/Crest-Whitestrips-Advanced-Professi...