Is there a philosophical discussion to be had about whether the evil doings of a talented artist actually reduce the quality of what he or she did? I have a feeling it has already happened on here in the past. For me, it doesn't change the quality, but just changes people's attitudes as to...
Some not mentioned (I think) yet - pianists/organists perhaps rather than keyboards - but
Bruce Hornsby
Chuck Leavell - played with the Allman Brothers Band and played the piano part on Jessica - the theme tune to Top Gear
Dr John
Gregg Allman
Allan Toussaint
Garth Hudson (The Band)
Edit - oh...