My gut instinct is to caution you against using intermittent extrinsic motivators heavily. Some self determination theory researchers-- such as Deci-- find prior reliance on extrinsic motivators causes a marked decline in intrinsic motivation when the same task is later performed without external rewards.
Personally, I would try to be seen modeling intrinsic motivation wherever possible. This could involve openly voicing the importance of a behavior as you do it to reinforce the unspoken message. That way, through introjection, the underlying character attribute behind the behavior is internalized as a part of the child's--or adult's!-- identity.
I agree with you 100% (well 99%)...
Although this does not apply when your child is 4.5 and STILL has not potty trained....then you don't care how many m&ms you have to give out (2 for pee and 6 for a poop) and for how long. It really won't bother you if you need to send a 1 pound bag home with your daughter in law from his wedding. You just want the pee and poop in the toilet. (not speaking from experience here...twice...but they faded out the m&ms naturally within a reasonable time).
