Interestingly, I get about a 5-10 wpm bump when I smoke marijuana.
I tried switching to DVORAK to see what the hub bub was about. Spent about two weeks with it but never attained the same speeds. I'd try Colemak but I'm not sure what I'd gain.
Keyboard makes a huge difference for me too. Apple's keyboards suck and can put a serious dent in my speed. I've been using the Moshi Luna and it's like playing a piano, though it's more cheaply made then it appears (I've been through two).
I'm fastest on an IBM Selectric typewriter though. When the fingers are blazing there is definitely a rhythm that you fall into that maintains that speed, so long as your brain doesn't jam up.