There are two very nice papers on David Hume and his monetary theory. The first one,
David Hume's Monetary Theory Revisited: Was He Really a Quantity Theorist and an Inflationist? by Carl Wennerlind (2005; Journal of Political Economy) HT to fg!
has won ESHET's 'Best Article Competition' in 2006. It is a wonderful piece of economics.
The second paper is written by Mark Thornton, an Austrian Economist (not from Austria, but a member of the Austrian School of Economics):
Cantillon, Hume and the Rise of Anti-Mercantilism (2006).
Good stuff!