IRS and identity theft

I just received a 5071C letter from the IRS confirming that someone had used my name and SS to request a refund. I have not yet filed my taxes so this was definitely some type of identity theft attempt. So good, it got stopped. But what are the bigger implications. Someone has my name and SS number. What other kinds of things should I do to vaccinate against other things they may do with this information?

Check your credit report:

There is good information here on additional steps to take: