I save a cleaned up file (skin retouching, geometry corrections, etc.) prior any kind of sharpening. This file also does not include any severe tonal adjustments.
For disk space saving purposes, jpeg2000 at 99% lossy quality is generally sufficient. There is no detectable loss of spatial resolution, and very minor loss of tones in shadows.
The purpose of this file is to be able to go back, but post raw conversion, to reuse all cleaning work and then generate a new tonal / color / sharpening interpretation of the image.