Originally Posted by bdublz
I second what John Clark says; I'm with T-mobile here in the states and got my phone unlocked for a recent international trip. Plus if you ever decide to sell your phone the value goes up a bit as it isn't sim locked to just one carrier.
Plus some negotiation leverage. I had recently bought a new phone (couple of years ago) when my carrier decided to stop offering my plan and move me to a more expensive to get the services I wanted. With my phone unlocked and threatening to leave they were willing to bend a bit.