Bill Gates 3

Formed the world's most profitable monopoly in the 80s/early 90s. Hasn't done much of anything since, except ruin perfectly good programs with endless useless 'critical' updates.   

Update (not critical):  The benefits of philanthropy shouldn't be calculated by how much money is given away, but rather by the results.  Carnegie and Rockefeller gave their money away wisely-and not just to avoid taxes, or because their wives pushed them to do so.  They also spent their money primarily where they made it-in the United States.  The same can be said of many contemporary philanthropists, but not Gates:

The main problem with the approach of Mr. Gates is that those he wants to help suffer from lack of productivity, which in turn is related to their benighted forms of government. The best thing he could do with his fortune would be to try to create jobs in the Third World, not put the social welfare cart before the horse of economic growth. But then he would face the real problem: lack of property rights and the rule of law. Once those are in place, no force is more creative than capitalism.

-Peter Foster, Gates' Shakedown Capitalism