Mobile Phone - How many Features if any, do you need?

The release of the Hop1800 'voice only, no screen' Mobile from Hop-On has made me think, what features of my Mobile do I use and I came up with a short list?

• Address Book for Voice/Text/Email and as a quick look-up for Landline, Fax Numbers and Email Addresses.
  
• Voice Calls
• Hands Free
  
• Text Messages (Many more in, mainly from Services such as Voicemail)
  
• Email (Mainly out - Passing Notes about me being delayed enroute)
  
• Camera (once in a blue moon).
• Internet (once in a blue moon).

One feature I sometimes think I might use one day is a data service connection for my Laptop, but the requirement has never arisen. So in theory I am using a reasonable number of features, but what if they weren't there?

• No Address Book - Back to good old Filofax :-)
• No Hands Free - Even Safer Driving as I wouldn't have the Phone Switched on.
  
• No Text Messaging - Have to check Voicemail after meetings, etc, otherwise inconvenient, but I think l I could learn to live without it very quickly.
• No Email - Not really a problem, if it wasn't there!
  
• Camera - If didn't have it, it wouldn't be missed.
• Internet - If didn't have it, it wouldn't be missed.

Now I accept that some of the above might be more of a problem if I didn't have a laptop, but for me the core requirements are:

1. Voice Calls.
2. Voicemail.

So what would happen if I stopped having a mobile?
As I have always treated Mobile Phones as a communication tool, not a necessary part of my lifestyle, I suspect that for a week I would be extremely irritated it was no longer available, but I also suspect those people used to calling me on the Mobile would be annoyed. In the longer term I would probably find that people would consider it very odd I didn't have one (in the 1990's I spent five years without a Television, something that was always treated with utter amazement and disbelieve).

To end, a couple of idle thoughts:
So how would others cope without a Mobile?
What would be the consequences of every mobile network going off-air for 24 hours?

Finally who is going to buy a very basic mobile like the HOP 1800 in Western Europe and North America?
OK other than Criminals, Terrorists and those who just want an emergency phone.
Actually the above probably means there is sufficient market for this type of device!