Level Up to IPv6 with Ubuntu 10.10 on Comcast (Linux.com)

"That would give people a easily understood incentive to find ways to avoid the need for public IPv4 addresses."

Assuming your emphasis here is on "public" rather than the obsolete IPv4 that's a perverse incentive, as if you were to deliberately penalise people for living close to the place where they work...

The "private" ranges like 10/8 are seen as a failure. Nothing quite like them is planned to exist in IPv6. The reason is very simple: networks get connected. It's lesson #1 of the Internet. Company X (using 10/8 addresses for its "internal corporate network" and Company Y (ditto) merge. Then the poor sysadmins spend the next six months reconfiguring everything from Cisco routers at Springfield corporate HQ to some Netgear switch in a cupboard in Whocares, Japan to get the two networks to connect safely.

So, globally unique (but not necessarily globally routeable) addresses are the future. You don't have to connect networks together today, but in case you decide to do so tomorrow we'll number everything uniquely now so that at least it will interoperate. IPv6 reserves space (the benefit of having sufficient space to allocate) for two likely mechanisms for allocating such addresses, one which appeals to businessmen and one which appeals to statisticians.

The statisticians get randomly generated addresses. These cost nothing, but there is an infinitesimal chance the other guy's network used the same address for a printer that you're using for the boss's laptop. Business people get an entity which sells or rents blocks of unique addresses for private use. Needless to say the statistical approach actually exists, and the other one is tied up in arguments from different people who all fancy a license to print money.