As far as deodorants go, nothing beats a mineral salt block. Not only does the $5 block last 6+ months, it eliminates ALL odor for at least an entire day if applied liberally.
Seriously, I apply the salt block in the mornings after I get out of the shower, go all day without any odor whatsoever, and wake up the next morning with virtually no odor at all. My underarms smell almost as fresh in the mornings as they did when I exited the shower the previous morning. This stuff is truly amazing.
One downside, however, is that it must be applied quite liberally, and must be applied to clean skin. It only prevents the growth of odor-causing bacteria, so if the bacteria/odor is already present, the salt block will do nothing for you until the area is washed with soap. The other downside is that this is simply a block of mineral salts, so it won't act as an antiperspirant. This doesn't bother me though, as I am allergic to antiperspirant bars.
Most local drug store chains sell mineral salt deodorant sticks and sprays. I urge everyone to try it if you haven't already.