You don't get any taxes back from a paycheck. In the US, an employer is required to withhold a percentage of your pay, based on withholding tables, as an advance towards your tax liability. After the end of the year, you receive a W2 form from each employer stating how much has been withheld and turned over to the various taxing districts (federal, state, local). You then complete a 1040 form that calculates the amount of tax you actuallly owe based on deductions and credits you may qualify for. This is then compared to the amounts already withheld. If more was withheld then you owe, you get a refund, if you owe more you have to pay.

SG was talking about federal withholding from your paycheck. The same explanation applies to any state or local income taxes that are withheld from your wages (if any). You also have payroll taxes (social security and medicare) which take 7.65% on the first $106.8K you earn per year - you don't get that back (though your contributoins to SS help qualify you to receive SS benefits in the future), and you may also have a state unemployment insurance and/or disability tax taken out (SSI/SSD) - you won't see that again, though it may qualify you to receive unemploytment if you ever lose your job.