Love the straw-man argument someone set up regarding "trickle-down" economics. Even if millionaires buy from other millionaires, it still goes towards economic growth and job creation. Who do you think makes the products? Workers. Who pays workers? Employers. What happens when employers get money? They spend it on one of two things: investment (whether in workers, machinery, R&D, or what-have you) or on products which are bought from other employers who are also providing jobs.
It's logic, people. When a rich guy buys something, that money goes to economic growth. When the government buys something, it typically results in paying people and/or businesses for NOT producing, or it results in blowing stuff up or paying people to kill other people. Roads (especially in cities), police, and general infrastructure maintainence are legitimate government interests - that's not what most of the money goes to. Governments are an astounding engine of wealth destruction, whereas private enterprise almost invariably results in wealth creation. The government is literally incapable of generating wealth - ALL it can do is re-arrange it. It is not a difficult concept to grasp.
Does there need to be SOME taxation? Well, duh, for such things as national defense - which, BTW, in my book does not include blowing up Afghans who haven't done anything to us. Defense is a perfectly acceptable reason for limited wealth destruction. However, to claim that the government can benefit more people by "soaking the rich" than the rich can by spending or saving it is mind-bogglingly absurd. Even if they are only interested in themselves, the rich still benefit the rest of us through job creation and wealth generation.