Are you willing to pay extra for an unlocked phone?

Yes, I will pay more for an unlocked phone.

i own  an htc one x unlocked phone and i paid full price  about 600$ v(with warranty)in lebanon

 actually  i never bought a locked phone :p 

  Yes,  I travel frequently and an unlocked phone gives me the choice to have a local number  for a small charge for the sim card and keep all the features I need in a phone.

Absolutely not! They should come unlocked. Give me a little agreement that says "I know I'm messing with the software and I understand that third-party software will not be supported by the carrier or manufacturer."

If/when I have a problem, I'll flash back to stock and return it. We shouldn't be SOL if we have hardware issues while running CyanogenMod. If I brick it, it's my own fault and the carrier will probably get another phone sale.

I own a Nexus S, which I bought from Fido, because their phones are all unlocked. The trade off was that I had to pay full price. I then put in my Rogers sim card, and called them up and negotiated a lower monthly contract.

When I moved to the US, I hated locked phones to begin with, plus mandatory data charges as I have wifi every place I go (except transit). I bought HTC Sensation XL at full price of ~USD550 and have been using T-mobile Pay-As-You-Go plan (1000 min.s for $100). Before this I did the same with Nokia E50 as it was released. Its worth as if you are not heavy user, you save a ton at the end of 2 years, actually enough to go for another new phone. With wifi available at every place I go, I use VoIP provider to make my calls (which is free to many countries including US and Canada).

So to answer your question, using unlocked phone, not to actually switch the carriers but not to drain money in greedy cellular service providers in the US.