Some months ago I wrote a quick blog post titled "Tones and Dynamic Range. Why You Should Shoot RAW". In that post I quickly analysed the shortcomings of files with low bit depths (such as 8 bits) and tried to give a valid reason why a photographer should always shoot RAW. Unfortunately, the limitation of the blogging platform and the time restrictions I've got make writing this kind of content awkward, at a minimum.
Here's a document featuring the same content, although better organized.
Notes on Dynamic Range, Gamma Correction and the Importance of Shooting RAW v. 1.2 (PDF)