My X100 Set-Up: I usually shoot at an aperture of f8 when doing street work. It gives a decent depth of field and should yield more keepers than if shooting wide open. Shallow depth of field (wide apertures) leaves little room for errors in focusing. I use Auto ISO set to a maximum of 3200, with the shutter speed set to a minimum of 125th sec. I find this shutter speed to be as low as a I like to go, unless I'm deliberately trying to add motion blur. The ability to set the Min shutter speed in Auto ISO is the main reason I prefer the X100 over the X-Pro1 and X-E1 (although I do use them for street from time to time). Another reason is the 35mm (full frame) lens that is perfect for street or documentary work. I also set Sharpness to Med-Hard (I tend to +1 the sharpness in all my Fuji cameras). I really like my X100 for street photography, but I think the X100s will be one of the best street cameras available! But with three X cameras in my arsenal, I can't justify the £1100 without offloading something first...or can I? One more thing...I use auto focus, rather than zone focusing.
Post Processing: My street photography post processing is minimalist to say the least. I'd rather be shooting than sitting in front of the computer! My basic workflow is this. Inside my Light Room pictures folder, I wave a folder called Street Photography (it took me a while to come up with that one). Inside that, I make another folder and call it Street Photog-(place)-(Date). I then throw the photos from the days shoot in there and then import them into LR4. I flick through them and hit P for pick for all the keepers. I then filter the Picks and if I want to narrow them down ever more, I hit 7 to flag it as yellow. Yellow tends to be for printing or blogging. I then send the photos that have been flagged as yellow over to Nik's Silver Efex Pro. I have three versions of a the same preset, one -1 stop, one +1 stop and one in the middle. I can basically hit one of these presets and it's job done. The preset is one that I've refined over the last year.
What I Look For: I look for anything that stands out. It could be the way someone's dressed, their hair, their skin might show a full lifetime of wear and tear. I like a bit of humour too, sometimes you see it at the point of capture, sometimes it's in post. Composition is a big thing and I always have my focus point over to the left or over to the right (rule of 3rds style). If I'm walking close to the buildings on a street, my focus point will be on the opposite side, because that's the side people will be passing me.
I hope this has been of some use? If I've missed anything pop it in the comments and I'll reply there or add it to the bottom of the post. If you found this post useful, you might also like The Digital Contact Sheet :: Episode 5, where I take a contact sheet and show how I choose and edit sone of my documentary shots.