You're not a world traveler until you're traveling with a brand new dual SIM quad band phone.  Dual Sim with dual standby means that you are in effect making your phone as good as two phones in one.    Slip in two separate SIMs and the phone now operates under two different numbers, which means that with just one phone you can take care of all your business and personal contacts without ever having to remember to bring both phones or switch between them on the fly.  More and more people are jumping on the dual SIM bandwagon, so consider purchasing one of Quad-Band-Phones world wide usage, unlocked dual SIM phones for your own.