That being said though - I disagree with the notion that meditation can lead to similar experiences. Meditation can certainly create very powerful and "spiritual" experiences, but only for people who are both extremely skilled meditators (which is not realistic to expect even 1% of the users of psychedelics to accomplish) and only while meditating (with psychedelics you can see/hear/taste/feel/experience the environment around you, not just the environment of your mind like with meditation).
Psychedelics should certainly be handled with extreme care (yet there's the paradox that being overly anxious/nervous about the experience may cause a bad experience), no doubt about it.
One of the cardinal rules of psychedelic use is to never do it alone though, his near-death experience in Nepal was due to breaking that rule. Being together with someone else isn't a guarantee of not having a bad trip/experience, but it's a good way to prevent putting yourself in dangerous situations like he did.
With psychedelics, the failure modes are a lot worse.
I feel like psychedelics are karmic time-accelerators, by a factor of about 100-1000. The good news is that, in a way, this means that you can have a month's worth of experience in a few hours. The negative is that, if there's something negative about to ripen in the next six months, a trip can have you encountering it immediately and deprive you of the time to react to it and get the help, or make the changes, that you need.
Also, there's a perception that "meditation" is closed-eye sitting, and that you don't get to experience the external world while doing it. That's not entirely true. There are walking meditations, for just one example, and one of the goals of many meditative practices is to bring that meditative mind into your daily life. That's easier said than done; it's quite difficult, to tell the truth, and probably not desirable, for average working people, to bring the meditative mind into all aspects of daily life.
All that said, these drugs shouldn't be illegal (even for personal use, what a person wants to do with his or her own body isn't the state's business) and they definitely deserve more research. I think they have a lot of potential and deserve further study, and that the stigma/illegality do more harm (in terms of supply problems, set-and-setting issues) than good.
Meditation is certainly the safer and less potent choice, nobody disagrees with that. Yet, I feel that the dangers of psychedelics are overstated, as long as you're careful and smart. Most of the bad experiences seem to come from a negative set/setting, not following the cardinal rules and too high of a dose. By starting with a small dose and gradually slowly increasing the dose for each trip you'll discover what your optimal dosage is in a gentle way with less risk of having a negative experience.
Research seems to back that up:
"One study found the most desirable results may come from starting with very low doses first, and trying slightly higher doses over months. The researchers explain the peak experiences occur at quantities only slightly lower than a sort of anxiety threshold. Although risks of experiencing fear and anxiety increased somewhat consistently along with dosage and overall quality of experience, at dosages exceeding the individual's threshold, there was suddenly greater increases in anxiety than before. In other words, after finding the optimum dose, returns diminish for using more (since risks of anxiety now increase at a greater rate)."
That, however, is another debate.
These are easy to state but hard to practice and hence the allure of LSD's IMO
As far as the "only while you're meditating" thing, zen meditation is interesting because (based on my limited understanding) zen is really about taking the practice of your meditation and extending that "mindfulness" into the rest of your life. "Zen Mind Beginners Mind" is particularly good if you're interested. Zazen is one form where you are eyes-open.