Forbes- It's Time to End the Drug War:

"April 20 is the counter-culture “holiday” on which lots and lots of people come together to advocate marijuana legalization (or just get high). Should drugs—especially marijuana—be legal? The answer is “yes.” Immediately. Without hesitation. Do not pass Go. Do not collect $200 seized in a civil asset forfeiture. The war on drugs has been a dismal failure. It’s high time to end prohibition. Even if you aren’t willing to go whole-hog and legalize all drugs, at the very least we should legalize marijuana."

I'm tempted to quote the whole (relatively short) article since it touches on just about every reason I support full legalization of marijuana.