Rule of thumb is to pay the higher interest rate first. I reviewed the scenario on my financial spread sheet and both payments are similar in payments and interest paid. However, the equity loan that you have, it is a loan or line of credit? If it is a loan, make sure it is a fixed rate. (I assume you have a fixed rate on your 1st mortgage.) If you have a Home Equity Line of Credit (HELOC) then I would definately pay extra on that one first then, because interest rates are on their way back up which would make your payment go up.
I hope this helps. Good luck!