Enough time has now passed that it's possible to take a look at the effect of these tax cuts on government revenues. The growth of receipts by source, outlays, and GDP over every 6-year period since 1940 is shown in the following graph:
The actual numbers and sources can be found at http://www.econdataus.com/recgro6y.html. As can be seen in the second table and graph, individual income tax receipts actually declined slightly from 2001 to 2007. Even total receipts were up just 9.4% over that period. Finally, GDP growth has been no faster than usual since 2001. Hence, although it's been just about six years since the 2001 tax cut and four years since the 2003 tax cut, the evidence to this point is that the Bush tax cuts decreased revenues over what they would have been, at least over the short term.
For a look at the effect of the Reagan and Kennedy tax cuts on revenues, see the analysis at http://www.econdataus.com/taxcuts.html.