Need it? No, I could live without.
But I desire one as I have two children and do a 12 hour day at work, so useful.
What's more having a blackberry means that I get work email all the time too, which is in fact handy so I don't end up with a a backlog, or handling a team issue on my arrival at work.
Useful because I cycle in a remote area by myself, and whilst it won't stop cranial issues etc, it does afford some level of security, if only to tell the other half that I'll be late home as I'm 'walking out' as has happened.
I have one because it's handy, but I won't be running up a 2k bill.

I have a Blackberry, which is very useful. I send probably 10 texts a month, and make perhaps the same number of personal calls. I like the fact that I can email with a proper keyboard.

As it's a work phone, I don't pay the bill. If I had to, I'd probably have a cheapo PAYG as a point of contact and for emergencies, but it'd probably go flat from lack of use.

Overall, I need one for work but could easily go without it on a personal basis.

elfinsafety – yes mobile broadband. I have two sim cards – one for my phone and one for my laptop. When I say I think I need my mobile maybe I should say I believe I need it. Of course it's open to challenge because once upon a time we didn't have mobiles at all and in fact having a telephone was not the norm. I can remember a sense of foreboding when the phone rang – if you wanted to communicate good news you wrote a letter, if it was bad you got a phone call. Times chaine and so do expectations.