I'm going to try whitening my teeth at home, but trays seem like kind
of a hassle, so I'd rather avoid them if possible. Colgate has a
no-tray system (http://www.colgatesimplywhite.com/flash.html) where
you paint the whitener onto your teeth after brushing. Other companies
are selling whitening creams which you use in place of toothpaste.
What brands work best? How does the effectiveness of techniques like
this compare to at home whitening using trays? Are these "bleaching
cream" tooth paste formulas (which my grocery store puts next to the
tray-based whitening systems) much more effective than Whitening
Crest, or any of those other, less expensive whitening toothpastes
(which my grocery store puts in the toothpaste section)?

Crest whitestrips are very effective compared to any toothpaste
available. I found them to be much better than I expected. They are
available for less than $30.00. They do work!