I remember voting in this a long time ago. I was really into acid and the whole culture of it so obviously at that point, it was LSD, now I think I'd be more tryptamine-centric; it would have to be 5-MeO-DMT for psychedelic purposes in the rather narrow sense, for recreation, more complex (for this purpose by which I mean having something more complex than dimethyl-T at the core) substituted tryptamines I think, something fluffy and friendly like 5-MeO-MiPT, maybe something a little bit more psychedelic like 4-AcO-DiPT. For clinical work (which I have never done) I think the latter, or the simpler OH-substitution might be good, too. LSD is still a powerful psychedelic and mythopoiec, though, and as the broadest and most promiscuous of the psychedelics pharmacologically the same qualities that make it so special also make it a bit of a blunt instrument of you have a specific appetite you want to fulfill, that is, except of course for the specific appetite for the special qualities of LSD.
(Random thought — have propylisopropyl-T substitutions circulated or even been made and tasted? I don't seem to recall reading about it though it seems obvious … wouldn't be legal in most places but might be interesting — though I'm not sure if China has an isomer clause, pretty sure they don't have an ester one.)
^ don't think I'd kick her out of my bed
When originally posting here I'd also have advocated for LSD as a first psychedelic, these days I would recommend a gradual path of introduction starting with something like a cocktail of 50mg 2C-M (2C-D), 15mg of Dexedrine and 2mg of diazepam as a first introduction to the psychedelic state, to be followed by in stages separated by at least a week by DMT and then either LSD or a more complex tryptamine (synthetic, not mushrooms), with DMT, smoked, with an moclobemide, or given i.m., as a possible insert between.
But realistically speaking; if I had to have only one to use or give, though, it would probably remain LSD, due only to its expansive pharmacological profile, but we are in these days spoiled for choice (or are we? I don't see a lot of discussion of these types of classic Shulginalia, I'd imagine because the most synth shops now cater to a less refined palate as well as pretty much his whole
oeuvre being illegal nowadays.)
This coming from someone who thinks and writes a lot about drugs but doesn't do them anymore (with narrow exception not including psychedelics. LSD I have thoroughly lost the taste, or the nerve, for, if I had some of the aforementioned complex/asymmetric substituted tryptamines, or 2C-M, now, that might be a different story.)