>We don't want to prevent Microsoft and General Motors ... from investing more and improving their product line

A lack of cash is not what stops these companies from improving their product line. Apple is sitting on $100 billion (maybe somewhat less now that they're doing dividends?). Corporate taxes are not preventing Apple from employing more people, they have no need for more people. If Apple were taxed less, they would not hire more people.

I am highly skeptical of the claim that removing corporate taxes would create jobs in other sectors as well. Why would GM need to employ more people if their taxes were lowered? Consumer demand is unchanged, they don't suddenly need to pump out twice as many cars. Innovation and improvements on product lines don't come from the number of product designers a company has.