They should all be legal, really (though this isn't practical for many reasons at the mo') - thus taking a huge economy away from criminals. If people want to **** themselves that should be up to them - legal status isn't going to make much difference. In fact it's the duality of some being legal and some illegal that makes the legal ones seem ok (as so well illustrated by BlueskyRich's overt hypocrisy) and so you see our hospital wards full of such casualties.
Smoking in a public place though... that's another matter altogether!