When I first heard about dual flush toilets I mistakenly assumed they were a particularly wasteful bathroom fixture for people with high fiber diets, but I was happy to lean "Dual Flush" doesn't mean it flushes twice, instead it has two flush modes in order to conserve water. What a great idea!
The Persuade from Kohler has two flush modes: an already low flow 1.6 gallon flush for solid waste and a reduced 0.8 gallon flush for liquid waste. Using this toilet in lieu of a traditional 2.8 gallon model will reduce your water 67%. The Persuade costs about $225 and some models cost much more, besides the expense, replacing a perfectly good toilet is kind of a waste so for those of us not remodeling a retrofit kit may be a better option. With a dual flush kit you can outfit your existing toilet with new innards turning it into a dual flush throne for about $50! The kit is fairly easy to install and if you have a screw driver, a saw, some pliers and some elbow grease you should be all set.