Passport (Check validity)
Visa / Alien Card (Check Valdity)
Ticket - Email/Paper
On-Line Check-in (if available)
Cash / Credit Card
Car Keys / House keys (leave unnecessary keys at home)
Address /Phone no. for Travel Destination
Photo Identification Card (Driver License, etc.)
Make copies of important documents (passport, visa, etc.) and put one copy in each bag
Luggage Weight According to Airline Rule
Keys for Destination
Tie a colorful stickers/tape to identify your bags quickly

Medicines
Swimming Costumes
Sun Glasses, Sun block cream
Lenses/Eyewear
Cellphone - Call your telepone provider to unlock the phone, enable international roaming or get a SIM card
Put vacation messages on email/voice mail
Camera (including batteries, memory card, chargers)
Laptop (including charger)
Ipod/CD Players
Put  Heater/Thermostate on Vacation
Close Garage, Doors, Windows
Stop Postail Mail
Stop Newspapers