I've tried most of these except the dreaded nutmeg. Why anyone would want to take that, I don't know... I think with these things there is a tendency to go through Erowid moving from the most appealing through to the most dangerous, in search of finding a good one.
I don't really find them useful, they've either been at best a mildly interesting one-time experience, or just a cheap unsatisfactory way to get high. As for all these ones people smoke to try to simulate cannabis, honestly you will never be satisfied and if you have to give up weed for some reason it is better to learn to live without dope instead, it takes time but it's worth it. Cactus is a good ally to move onto if you can't face sobriety, coca too but that's not necessarily legal, can't help you with getting used to sleeping without weed though. Valerian and passionflower are alright as sleep aids, but better is to have vigorous exercise early in the day so you're physically exhausted at night.
If I ever have kids, I will tell them don't bother with the plants listed in this thread so far, and that cactus, ayawaska, coca and tea are the true plant teachers and helpers (a little weed at some point in life if you like music, but know when to stop).
Entheogen.org (Edot) has a lot of people into these types of legal highs, there's lots of useful info there, but many of them are taking a selection of things daily and it seems to me some of the behaviour patterns seem a bit 'plant junky'. But I understand, you guys will want to find out for yourselves, so don't mind the old man, and be safe with your experiments!
Everything I write is fictional roleplay. Obviously! End tribal genocide: www.survival-international.org Quick petitions for meaningful change: www.avaaz.org/en/
End prohibition: www.leap.cc www.tdpf.org.uk And "Feeling Good" by David D.Burns MD is a very useful book.