An LLC is supposed to eliminate double taxation. But doesn't one get payroll-taxed AND income-taxed on profit?

I agree with Judy. Two additional notes (1) the "no double tax" for the LLC concept relates to the fact that the LLC does not pay a corporate level of tax like a corporation would - all of the income flows to you before it is taxed a the "single level" that is you. That doesn't mean, unfortunately, that at your level you cant still get dinged with many different kinds of taxes such as those you mentioned. (2) the medicare piece is only 2.9% (out of the 15+ percent originally paid), so I guess that is the good news if you earn six figures.