I'm in the exact same boat as you! Started out completely ignorant to drugs, but now i'm in college and it's really easy to explore this side of human nature.
The first drug (aside from weed) I tried was XTC. Basically mdma, mixed with random additives (amphetamines, caffeine, fillers etc) pressed in to a pill. At first it took so long for us to even feel anything we thought we'd been duped. After it hit though, damn.. Gave me incredible energy, suddenly I had amazing dance moves, socializing with strangers was amazing and after the party I had the most open, wonderful convo's with my friends. All of the other 5 times i've done XTC were like this. Incredible energy, fun to dance and talk, and an incredible feeling of love. Basically, every party/concert/festival you do on XTC is the most amazing one you've been to, everything just feels perfect at that moment.
I've also done pure mdma. I did this a week back with a friend and a girl-friend. We did this in a chill setting as opposed to a party, we just hung out on our bed. We were completely platonic friends, and the girl even has a boyfriend, but within no time after it hit we were cuddled up on my bed, topless, jamming to the music and having the most incredibly open, heartfelt conversations all night long. Really, if there's one thing on that list you should do is MDMA with close friends in a chilled setting. IMHO it should be a bucket list option for every human in earth :P (bonus points if you bring a hot chick friend 'cause you'll get to feel her boobs up all night. she was totally cool with it afterwards too).
on the day I did MDMA with those friends we made a pact to finish our "drucket list" together. So far I wanna try shrooms as my first psychedelic, then LSD, then a combination of LSD and MDMA (supposed to be incredible). Also, DMT, and 2CB. As for other stuff, look in to Ketamine too, and stimulants like 4fa. Cocaine is dangerous, combine it with alcohol and your at risk of a heart attack. That being said, i wanna try it too some day.
I have no experience with peyote. You should def add DMT though, it's supposed to be the end all of psychedelics, look up some trip reports!
As for your "drug culture" question, here in holland it's definitely XTC, it's a really popular drug that pretty much anyone here does sometime, and the quality of it here is great.