Mine are weed and meth.
Marijuana gives me different perspective. Sometimes I make life changing decisions when i'm high, and sometimes I wish I were high before making life changing decisions. Basically, I feel like every so often one should be slapped in the face with reality, and that's what weed does for me. It allows me to proceed with more caution.
As for meth, I just love stimulants. A long lasting aphrodisiac that makes you feel pretty neat. It's already taken a toll on some of my teeth, my subconscious and my wallet, and am looking to cut down, but I just keep coincidentally running into better after better batch. It's like every time I cop the stuff just gets more potent. I'm trying to find the ending point, so I can say, "hey, madness.. although you've found the top quality for the street, you're still blowing through a gram per day. This is not economical, and you're damaging your dopamine receptors among many other things". You know. That's your ego, right? Telling you to be careful and all? My therapist says I live in "id" land, with a weak ego and more or less a superego that took an extensive vacation.
Least favorites?
Pain killers - make me tired.
Benzos - make me too uninhibited/drunk-like, and somewhat tired.
Heroin - Only in speed/goofballs, otherwise makes me tired and nauseous.