Erik Altieri of NORML calls November 6th the "the biggest Election Day in the history of marijuana law reform":

Consider that the first state to pass a law against marijuana was Massachusetts in 1911, 26 years before Congress passed the Marijuana Tax Act. During the 26 years between Massachusetts’ law and the Tax Act, nearly 20 other states passed anti-marijuana laws. Solidification of marijuana prohibition came more than thirty years after the Tax Act, when it was listed as a Schedule I Controlled Substance under 1970’s Controlled Substances Act, after which marijuana arrests began to balloon. The lesson here is that changing established public policy is not something that can be accomplished uniformly, quickly, or easily. But, nationwide policy is more likely to change as more states join in, and this November could very well bring about the first state to vote for legal marijuana. If so, it will likely be the first in a long line of states to do so before the Federal government.