for me it will always be Cliff Edwards.
perhaps a better question would be directed to artists within particular genres,
as there are so many fine, fine instrumentalists past and present who really have excelled
within certain styles of music. for example: jazz, traditional, blues, ragtime, tin pan alley and etc.
James Hill is one who crosses and blurs all boundaries. Has to be the most well rounded player we've seen so far.
that said, and notwithstanding the wonderful players already mentioned,
several more for your consideration/exploration:
Azo Bell
Lyle Ritz
Bill Tapia
Lil' Rev