I really think the 90's was a "perfect storm" for fiscal responsibility. You had Bush Sr and House Dem's big tax increase in 1990 (because spending was ballooning out of control). Then Clinton came in and shifted the tax burden back onto the rich in 92-93. Then the new Republicans stormed into office in 94 with a mandate for balanced budgets and less pork. Of course, they forgot about all that in the next decade .. but they did awfully well those first few years. Then on top of all that, we had a massive decrease in military spending and no real major conflicts to deal with.
With our (apparent) need for federally funded health care, baby boomers hitting retirement age and the added costs of rebuilding infrastructure ... I can't imagine us ever getting back to those levels again (even if Obama goes back to Clinton's tax plan).