On the issue of taxing investment income, it looks like Joseph Stiglitz is thinking along some of the same lines as I was a while ago. Here’s my version:

We already tax different kinds of investment income (e.g. short vs. long term) differently, so let’s create many more classes of investment income according to the rule that every level of separation from productive reality increases the tax rate.

Here’s his:

Why should those who make their income by gambling in Wall Street’s casinos be taxed at a lower rate than those who earn their money in other ways?
Capital gains should be taxed at least at as high a rate as ordinary income. (Such returns will, in any case, get a substantial benefit because the tax is not imposed until the gain is realised.)