Camera or Video Camera, memory disks, batteries, charger/power cord.
Plastic bags (Ziplocs work great!) to cover your electronics.
Extra money for drinks, tips and souvenirs in Soles.
Make copies of passport, visas, driver’s license, airline tickets/schedule, travel itinerary, credit cards (front and back), traveler’s checks’ numbers, frequent flyer numbers, travel insurance, and emergency contact information. Leave a copy with someone at home and put a copy in a travel companion’s luggage and email them to yourself (or Google Docs).