I'd think drug probihition is a bad idea in general. If you make something illegal, the price of it increases greatly, as it becomes a lot harder to obtain. If you legalize ALL THE DRUGS, you sweep the carpet from under drugs barons and, say, the Taliban (Who greatly profit from the drug trade, the hypocritical bastards).
Off course, legalizing ALL THE DRUGS is a bit extreme. The current dutch system is rather silly and broken (trading and consumption carries no penalty, but is still illegal technically) . Producing drugs is entirely illegal, and only very small productions won't get you prosecuted or fined), however, the idea is a good one in principle. Making drugs sellable under license (which is effectively what is happening now) is rather an effective measure of letting people experience drugs (because a lot of people want to do that for some reason) without doing it secretly, which tends to create certain... unsafe situations. These happen less when drugs are consumed in a room where they are sold by... experts, who have amuch better grasp of which quantaties are good and which ones are not.