Depending on your circumstances, including credit card purchase of tickets, medical insurance coverage, and homeowner's insurance... we highly recommend that you consider the purchase of additional supplemental insurance covering such issues as trip cancellation, medical emergencies, and theft of belongings. Below are a few web sites that give some information on this topic.
Be sure to make and carry separate printed copies of your passports, credit cards, driver's license and insurance documents, as well as make, model and serial numbers of valuables such as cameras, laptops and cellphones. Back up digital images of these documents and items, and store them on inexpensive "thumb drives" as an excellent extra precaution. These also provide a way to store "insurance" copies of your digital vacation photos while on your trip.
WikiTravel - Travel Insurance
Insurance Information Institute
USI Travel Insurance Services
InsureMyTrip.com (policy comparisons)