Is it time for a financial transactions tax?

As part of the potential recovery of bailout funds to banks, many have suggested a financial transactions tax, perhaps 0.05% on every stock sale. The British are now considering it seriously, and Oxfam, a British nonprofit advocacy group, is lobbying furiously to get the so-called "Robin Hood tax" passed (really, is that the best name they could come up with?). The U.S. government won't go anywhere near this, but it's an intriguing idea, as the following ad demonstrates.