I think that all this talk about a National Sales Tax is just political year rhetoric by Dubya and Rove. Even Dubya backed off the idea a few days later in yet another in a long line of recent flip-flops.
Everyone pays taxes, but some people have child credits, personal and family exceptions, and Earned Income credits that push them into net refund amounts, and I think that is where your problem with taxes seems to be. Personally, I don't think it's a bad thing for large families to receive refund checks, even on money they didn't pay into the system. A deduction for the poor should mean no less than a deduction for the rich.
Corporations are allowed to deduct, or rather, accrue all their business expenses. C.E.O.'s are payed in stock options to avoid paying taxes. A speculative loss here to avoid paying taxes on a large gain there. Tax credits and federal subsidies.
Instead of picking on the poor why aren't conservative talking about the welfare-state that corporations have built in America for themselves?