I prefer a fairly natural look to photos so they will age well. A quick preset mostly setting the Adobe color profile and some vibrancy/contrast.
For landscape shots I have vignetting correction turned on but not distortion (vignetting looks bad, distortion is not noticeable and correcting it reduced corner sharpness), for portraits and wildlife it is the inverse (slight vignetting can be helpful/desirable, distortion is not), and for architecture it is both.
When processing the most common tweak will be a little exposure, shadow and highlight adjust to get the dynamic range into something more displayable and printable.