Unemployment benefits: Unemployment benefits are taxable on your federal return except for the first $2,400 in benefits, which are tax-free for 2009. Unemployment benefits are not subject to Social Security or Medicare tax. Nor are they taxable on your California income tax return, although some other states tax them.

If you did not choose to have 10 percent of your unemployment check withheld for federal taxes and did not make estimated tax payments, you could owe more than you were expecting.