The main reason I originally got cell phones was to have a phone with me in my car in case of emergency. I could get along without it in my life but I still take it in my car with me.
A cell phone, or mobile phone as we civilised* people call it (*just teasing btw) is the number one safety device, if you go out anywhere really, especially alone, you should have it with you - you can call, you can take pictures of a crime/accident etc. It's also useful - a PDA, phone book, library, a way to access the internet to look things up and a way of keeping in touch with friends and family...
So, for me, it's important - I love it, I value it but it is just a tool, it's not IT I love, just what it can do.
Important... ? Well,, sometimes. I bought it primarily for emergencies, car breakdowns and so on; but given that the services are patchy it'd be just my luck if my car were to break down late on a Sunday night in some area where you can't find a decent signal!
It has been useful at times but I don't live my life by it, and you won't see me barging through the streets, head down, with the thing stuck to my ear. Or shutting myself from some social gathering because answering some text or other that can wait, is more important than the people around me.
I've two - an older, basic phone-first Nokia instrument, and a new LG thing whose phone side is very difficult to use, secondary to its text service, and to its Internet services which won't use. The PC is for that. I'm slowly working over to the Nokia only, on PAYG only, as that's far cheaper for me than a contract.
That terminology debate amuses me; in a rather cynical way. I know why the Americans call their radio-telephones "cell" phones - it's from "cellular", referring to the physical arrangement of the networks. "Mobile" though? Some semi-illiterate advertising-copywriter/marketing-executive type in the UK called them that, and so many people missed the mistake that it stuck. The telephones are not "mobile". They are "portable".