Is the tax rate higher for income or capital gains?
I've already accumulated about $45,000 in short term capital gains this year. I need to liquidate another $40,000 in stocks or sell part of an inherited IRA which, as I understand, will be taxed as income. Is the tax hit going to be the same either way?
Last year I had taxable income of about $53,000 with next to no capital gains. This year I expect about the same taxable income plus the capital gains.

Short term capital gains are taxed at the same rate as ordinary income. Long term gains are taxed at a lower rate.
Try not to take the money out of the IRA if you're under 59-1/2 – you'd get hit with a 10% penalty in addition to the taxes as ordinary income.
1All your short-term capital gains are taxed as ordinary income. They are added to your other income of $53,000. This will put you in a higher tax bracket of course.
The distribution from your inherited IRA is also taxed as ordinary income. There is no 10% penalty for distribution of an inherited IRA.
Check with the trustee of the IRA and a tax advisor to see if there is a way to stretch out the distributions to minimize taxes.
2