If by sedating/intoxicating you mean a total waste of time coupled with placebo, then yes, you're right.
The reason why I'm making this thread, is to prove to myself that with all the herbs on this planet people try to smoke, there is only 2-3 that are actually worthwhile. Salvia, weed, tobacco.
Wild Dagga is certainly not just a placebo high. If you don't believe me then maybe you'll believe erowid, where it is most certainly viewed as a drug, albeit a fairly mild one-
http://www.erowid.org/plants/leonotis_leonurus/leonotis_leonurus.shtml
I've smoked it a few times because I grow Lion's Tail (it's a very cool looking plant), but it's not particularly good. Basically it makes you tired and has kinda similar effects to cannabis. I've used it to make me nod harder before, with some success.
About smoking peyote- you can do it but there's not much of a reason to. Back in the day I used to smoke chunks of San Pedro in fact, and after smoking enough of it (a few in. of the bright green area directly under the skin) I could feel some mild effects for ~30 min. It's probably very bad for your lungs though, and if you do smoke it you must peel it first if you want it to be easy to smoke and not covered with horrible waxy skin.
I was going to say Datura but I think that's been mentioned. I was once a chronic datura user (daily for months, I was younger and stupid and rarely got totally delirious on it). I tried smoking the leaves, seeds and flowers, all of which worked. Datura sucks though, so it's another that shouldn't be smoked. But it is definitely a plant that works when smoked.
Also, the salvia you are smoking (whoever said salvia) is most likely an extract of salvia that is then poured onto plant material. Smoking salvia without first extracting it doesn't really work (it works but you have to smoke a lot). The salvia most of us have smoked is not a raw plant material, it's a plant extract put onto plant material.
Poppies contain smokable material so they kinda count. There are some traditionally used plants that are unknown to us in the western world. South and Central American Shamans smoke many kinds of plants and claim effects from many of them. If Carlos Castaneda is to be believed, there are plants in Mexico that can trigger super intense trips when smoked, including a kind of mushroom and several other plants.