I wouldn't give mine up for (just about) anything.

It is absolutely essential for my work. I am out of the office several days of the week, yet I am always able to respond to client emails. I am still able to respond when I am on vacation. Sure, that may not be what everyone wants to be able to do - be always available even when on a trip - but I run my own one-woman business in a highly competitive field. Being accessible and responsive is hugely important.

It's also very helpful for the work I do with TNT.

It's so nice not to be gone all day and return to 75 + emails which all need a response. I will have dealt with most of them by the time I get back and they can be filed away.

I have had a smart phone with email for over 10 years. I started with an early Palm version and now am on a windows mobile version. I toy with the idea of getting the iPhone, but I don't know for sure that it would sync with my Microsoft Outlook, which is critical.