Matt Laur , Jun 24, 2009; 09:37 a.m.
Storage (in the camera, and on the desktop) is fast and absurdly inexpensive. Shoot both, and avoid having to think about what is, or is not a difficult lighting situation. If it turns out it was a difficult situation, you can fall back to the RAW file with a couple of mouse clicks. If you're otherwise perfect while shooting, then all you've done is used up $3 worth of disk space. You'll never get more important insurance that costs so little.