There is an excellent debate between Geoff Mann and Robin Blackburn in the latest New Left Review on the political opportunities offered by the financial crisis - excellent because I agree with both positions. Mann makes the argument for the necessity of rupturing with the value form and the essential concept of real abstraction, while Blackburn notes what might seem his minimalist position in fact supposes 'financial dual power', through implementing something like a new Meidner plan. Blackburn also has an amusing anecdote about populist attempts to get all derivative and futures trading banned as inherently deceptive... The 1905 judgement by Oliver Wendell Holmes agreeing futures could be traded took arguments from Holmes's friend William James - with the pragmatic concept of truth involding credit / agreement on value (the anecdote is discussed in this fascinating article, which actually explains what futures are - they are as weird as I thought).
The relation of metaphysics to value (again).