Raising taxes on the richest one percent appears to increase tax revenues without lowering economic growth. Here's Lane Kenworthy with the details (this continues the discussion here and here; there is also a graph showing effective versus actual taxes in the discussion of fairness that does not appear below):

Taxes at the Top, by Lane Kenworthy on Taxes: For many progressives it is an article of faith that tax rates on the richest Americans should be higher than they currently are.

Why? One reason is that it would be fairer. ... Some opponents of higher tax rates for the rich argue that fairness in taxation requires that everyone’s income be taxed at the same rate. Taxation should be proportional rather than progressive. Not many people seem to share this view, however. Most feel that because they can afford to, the richest should pay not only more dollars but also a larger share of their income.

A second rationale for higher taxes on the most well-to-do is that it would increase government revenues, which could be used to help improve opportunity and outcomes for those less fortunate. Health care for all, a more generous Earned Income Tax Credit, and subsidized preschool and child care are among the many good ideas currently on the table.

The taxes paid by those at the top matter a great deal for government finances. As of 2005 the top 1% accounted for 28% of federal government tax revenues. That isn’t because they are taxed at an outlandish rate; an effective tax rate of 30-40% is hardly confiscatory. Instead, it’s because they get a very large share of the country’s income — 18% as of 2005.

The following chart shows federal government tax revenues as a share of GDP by the effective tax rate on the top 1%. The data points represent each year for which data are available. Although the correlation is far from perfect, tax rates on the richest are positively associated with the portion of GDP collected in taxes. This is as we would expect. It suggests that steeper tax rates at the top are likely to bring in more revenue.