I say legalise it.
In UK it has been decriminalised - pretty much ok to have a smoke at home as long as you're not dealing or growing loads. Police will only give you a caution if you are caught out and about with small amount on you for personal consumption. Dealers get hammered more tho.
I have had several periods when I did smoke weed, not in one at the moment tho. I think in moderation there is not much harm done. Right now in UK there seems to be a campaign telling everyone you get brain damage from smoking it, but what they ommit to tell us is that you have to smoke a 5h1t load of it for this to maybe happen. Basically too much anything is bad for you.
I think there is no doubt that its not good for your health but I hate all this sensationalisation of it in the media. I'd like to see them disclose the damage to a human done by spending a week in a big city and breathing in all the various fumes found in cities - or even a lifetime's worth

.
The reason I'm not smoking weed at the moment is because I don't want to, not because its illegal, and if it did get legalised tomorrow I still would not be smoking it - but it would be nice to have the choice of having a bit of a toke if the situation required it - much like having an alcoholic drink.