Drug laws are really screwed up IMO. 90% of the public, extended to 99% of MPs and Lords have no idea about drugs other than the old-fashioned stereotypes they were fed as children.
These are some of my experiences:
Cannabis: I don't see what the fuss is about really. Yeah weed is alright for chilling out if you smoke a small amount, but getting ridiculously blazed seems pointless to me as I just feel sleepy and the room spins a bit. However, I have had those few experiences when you laugh at everything and generally have a good time. At the end of the day, no matter how much weed you smoke, you're only going to get happy, hungry and tired. Why being happy hungry and tired is illegal with a 5 year prison sentence is just insanity.
Ecstasy: Avoid unless you know and trust the seller very well. E pills are fun and make you feel happy and talkative. No problem with them at all in a decent form. The problem is that most pills are mixed with other stuff and cut with other drugs and ingredients which can cause harm, so I steer clear of the pills just for safety.
MDMA: For anyone who doesn't know, MDMA is what makes Ecstasy pills give you that "up" feeling. That is to say that MDMA powder is pure ecstasy that isn't in pill form and hasn't been cut down. This is way better as you can directly control what and how much you take, and you can see the quality of what you get before paying for it. Little more tricky to take as you need to either rack up 1/10th of a gram line and snort your lungs out, or wrap it up tight in a rizla and swallow it. Swallowing or "bombing" it is worth it though as although it takes half an hour to an hour to kick in, it lasts WAY longer. I prefer to mix the line into a small amount of water and squash and drink it, as it works even better then as it doesn't have to pass through your stomach before hitting your water and then your blood.
Be very careful with MDMA. Don't take it more than once or twice over a 3 or 4 day period. I took way too much and was coming down for a week, I felt really depressed and anxious. I was scared of being alone and couldn't eat or sleep. The science is that MDMA makes your brain use up all its serotonin (the chemical that controls your mood) at once so that you feel stupidly happy and want to talk to everyone about everything! But it takes a while to replace this serotonin so you might feel bad for a while if you take too much.
MCAT: Same as MDMA really but a kind of nervy trippy feeling towards higher doses. Probably wont do it again as MDMA gets the same feeling and doesn't taste as bad (MCAT tastes HORRIBLE. I MEAN HORRIBLE.)
LSD: LSD is beautiful. Taken in 'tabs' (little squares of paper with the acid soaked in to it) they make everything trippy and interesting. Lights and sounds feel alien but fascinating. Don't take this when you're feeling bad though as it will intensify the negative feelings.
Salvia: Salvia is legal in the UK and you can get it in any head shop. Salvia is my favoruite drug. Smoke it in a bong or a shotty with someone around to keep any eye on you. Don't do too much the first time (about 1/5th of a gram if you get x10 or x20 will be ok). Everything looks and feels weird. You're sense of what is yourself and what isn't is distorted. One time I thought that I had turned into the night sky. Sounds ridiculous I know but I was sure as hell that myself, and the night sky, were on being that flowed into each other. Trippy but hilarious stuff.
Opinions:
I don't think (what I consider to be) "hard" drugs should be legal e.g. Heroin, Cocaine, Crystal Meth, Methadone most Barbiturates. They are just SO harmful and so addictive that the link to crime, and the detrimental effects on the person and society as a whole are far too great and numerous to justify.
As for Cannabis, MDMA/Ecstasy and other amphetamines like speed, trippy stuff like Mcat, Ketamine, mushrooms, salvia and LSD (which is far less dangerous than alcohol or tobacco) - these should be made legal (kept so in the case of Salvia).
Of the several drugs on the second list I've tried none have made me want harder drugs like the media might have you believe in their false "gateway drug" argument.