I am going to vacation in Mazatlan Mexico in December. Can anyone advise if I should convert my US Dollars to Pesos before going, or can I just spend dollars for everything. Or combination of both? What is the best way to get more value?

We are going to Puerto Vallarta, Mexico this month, is it best to use Travelers Cheques while we are there?

I agree with what has been stated in earlier responses. As long as you're staying in a major tourist center; take a moderate amount of USD and convert enough to Pesos to buy souvenirs, drinks, and food on the streets. When necessary replenish the Pesos using the ATM machines. ATMs generally provide the best exchange rates. Changing Dollars for Pesos in small shops is usually the worst exchange rate. For any major purchase use a credit card. Never dispaly a large wad of cash (Dollars or Pesos) when paying for an item.

have fun