Work at a nice big desk. I have recessed ceiling lights with a dimmer, and work from a basement office/entertainment room, so it's quite easy to set the right mood and be free from distraction. My chair isn't anything special: back-rest squeaks a bit, no armrests (who needs them??), and just enough of a cushion. It's not totally falling apart just yet, so it does its job.
I work from a dual 450 G4 with two 19 inch CRT's and a high refresh rate (prevents eye strain to an extent). I do nearly all of my pixel work in Photoshop 3.0.5. I built up some proficiency with mouse-based drawing, so I rarely use a tablet for pixel related work.
I'm not so much a slave to substances as other artists here appear to be.
I can roll right out of bed and work, and I'm not too fickle about the environment. I prefer to pen out a score of art at a time over a couple of hours, but it really depends on the first ten or twenty minutes: work can be daunting at first. If I'm not cursing myself for doing a poor piece, I'm spending several hours pouring over details, double checking as well as admiring. I spend about as much time pixeling as I do just looking at things. If I have a really good day of pixel work, this can translate into a chain of good days that keep me up late at night (or into the light of day...).
Of course, I do have a few preferred pixel aids to keep me at the terminal longer, such as snacks: a glass of water or juice (apple cider, cran grape, orange juice), or some sliced fruit (peaches, pears, or pineapple). Salsa and chips or hot chocolate are also useful if I need to boost my attention and comfort.
I like having some music. If I pixel in silence too long, my mind can get restless even while pixeling. I listen to any music (metal, electronic, rock, post-punk/new-wave etc), but I often resort to classical or dream-pop. Too much audio pizazz can diminish my pixel-time in the long run, so it's always better to side with low-tempo works. Guess it really depends on the subject matter.
What I really need is severe social trauma
Heh... I prefer the calm and cool logic of an emotionally quiet mind. Trauma and familial distractions can really take me out of the zone, but I've grown to subconsciously block most of that out. Still, people breathing down my neck all the time can be a bother.