in camera i set everything to zero - sharpening, saturation, contrast, etc. but since i shoot everything but team sports in RAW, the camera setting is pretty much irrelevant.
i spot pick the white balance (using something that is known to be white or grey) which adjusts the relationship between red, green, and blue channels. if i have no reference colour for the lighting (like a landscape or macro), i'll manually adjust white balance (best guess) and often slightly bump blue and green channels (since the Canon CMOS tends to be very red sensitive).
i make a slight levels adjustment at the low end and high end (like a contrast enhancement, but leaving the mid-range alone.
if i'm exporting to jpg, i usually convert from Adobe colour space to srgb (or embed the colour space profile) and increase the saturation about 2 or 3%.
all of this is done through Aperture as part of my workflow. it's very quick and easy and it allows me to post-process thousands of images pretty quickly.
overall it depends on my subject - and who will be viewing or buying the photos