Incidentally, just because conservatives need to think hard about infrastructure doesn't mean that they necessarily need to embrace infrastructure spending as stimulus. (See Brooks today, for instance.) On the that front, the case for pushing a payroll-tax holiday seems pretty strong to me - but then again, I'm always up for weakening the payroll tax.
The U.S. is particularly miserable at putting aside money for the future. Should we blame our paychecks or our psychology?