How Much of a Difference Can Liberal vs. Conservative Economics Make?

[ransomedbyfire]

I am a finance major and am almost finished with my third economics course. It is well-known that all my economics professors (3 of them) have favored conservative economics. They say that taxing the rich hurts the economy (as my Political Science professor puts it, "You get less of what you tax.") So, yeah, I know it's kind of a bad idea to "punish" the rich via taxes, but my question is: Does it really make all that much of a difference? Are we really gonna mess up the economy by taking a little bit more money from Bill Gates and giving a little more of it to me?

Also, isn't conservative economics basically making the rich richer, the poor poorer, and the middle class disappear? And isn't a strong middle class vital to the survival of a democracy?