[maxtower]

FICA limit:
The 6% you pay in social security taxes is only on the first 95k you earn as an employee. Someone who earns 150k will pay 6% on the first 95k, and 0% on the remaining 55k, for an effective rate of 3.8% FICA tax. For a person earning 50k/yr, they will pay the full 6%.
The reasoning behind this is because there is a cap on SS benefits.

Because of dividend and capital gains taxes being lower than income taxes, rich people tend to pay less (percentage wise) too, since a larger percentage of their income will be in the form of dividends and cap. gains rather than wages.