The Dutch experience is interesting. For all that it is 'legal' in Holland, or rather 'tolerated' I found the whole experience of an Amsterdam 'coffee shop' rather sad, seedy & unfortunate really.
As a side note to the progressive nature of Dutch attitudes to drugs, one program I was quite keen on some years back was the 'Harm Reduction Strategy.' An official tester would analyse your drugs (permissible drugs only inc MDMA) at the door of a night-club and advise on content. This, I thought was an excellent way of ensuring that under par crap manufactured by criminal gangs would gradually be reduced. What happened? It was unworkable and they gave it up. Like many progressive societies, Holland has been at the forefront of this kind of strategy for many years, including the legalisation of prostitution.
But, if you visit Amsterdam today, you'll find police anti drug activity at a similar height to most other Wester cities. The 'easy drugs' and general tolerance attracted a huge amount of attention from international criminals and Amsterdam became awash with them, seriously impacting on tourism.
You can still have a City Legal shag though. Just be careful you know what's 'down there' first though.
I have been hearing the argument of pro legalisation for many years and nothing I've seen or heard of the issue (remembering that I have worked with and around addicts pushers and major criminals plus provided HMG with consultation material for illegal drugs use in clubs strategy development), has led me to believe that legalising will do away with the criminal elements. They will just devise new and more exciting stuff that will make 'official' supplies look boring. And then what will you have? The legally elected Govt of the day competing with criminal gangs for your next hit.
Cannabis is different. It is a softer drug for sure but if a way could be found to reduce the illegal growers I would be interested in exploring some kind of 'understanding' about possession for personal use, which we already have in place here - in the guise of 'street cautions'.
To even contemplate legalising some of the dreadful stuff out there, to me personally, after recalling some of the things I've been involved in, is quite frankly an appalling prospect. I would definitely have a foot in Dimi's camp for that solution.