Personally, I carry two, one for business use, one for personal, so I can turn the busness one off when appropriate (the personal one is always on).
i don't know what I would do without my mobile. It does all the regular phone stuff, has a camer abuilt in (useless function as far as I can tell), and has a built in full function PDA. I get my important Emails there, keep my appointmnet book, etc.... AND, it syncs with my office network anytime I walk through the door. I hear the litle "bing bong" and I know that all is right with the world.
Personally, I think that poor rate plan availability is part of what is keeping more widespread use in America. Once we see unlimited usage for a reasonable monthly price, including data access, we will, I think, start seeing cell phones replacing land lines. Until then, that will be the exception, not the norm.
If ye love wealth greater than liberty, the tranquility of servitude greater than the animating contest for freedom, go home from us in peace. We seek not your counsel, nor your arms. Crouch down and lick the hand that feeds you; May your chains set lightly upon you, and may posterity forget that ye were our countrymen. —Samuel Adams