Tax day has come and gone, and about 100 million Americans have filed their income-tax returns. For all the grumbling about complexity -- fair enough, tax filing is way too complicated -- most of us understand that taxes pay for defending our country, protecting our environment, building our roads, educating our children, and all the other essential things we depend on government to do. One thing most people probably don't realize, however, is that almost a fifth of the income-tax dollars we send to Washington aren't spent on these kinds of important programs. Instead, this year more than $170 billion of our money will be paid out in corporate welfare.