I don't have a DSLR, so I shoot with minimum contrast in all of my cameras to try to get the most dynamic range I can. I also shoot with minimum sharpening. I have a batch Photoshop action that cleans them up for normal viewing and I also keep the originals for anything I want to work with in Photoshop. Auto-contrast is safe and just brings the contrast to normal levels, so that is what I use in the action along with some defogging, a tad of saturation and some sharpening.
Auto-levels usually does better than auto-contrast but can really mess up a shot on occasion if the lighting is odd. It can shift the color because it is adjusting all of the channels separately. It is easy enough to apply auto-levels to a layer and cross check it against you best efforts. It does a nice job in most cases.
I'm going to wait for Minolta to come out with their DSLR before I buy one. If they do a decent job and come out with some good lenses for the APS sized sensor I will likely get one. I've grown to like IS and would just as soon all of my lenses were stabilized. My best efforts with a prosumer can't compare to DSLR in the hands of someone like you who knows how to use it.