You can still strip identification for things like posting in public forums, but for everything else knowing where shit came from is critical. From spam email to well everything. It baffles me that spoofing callerID is not only possible but that some people think its important.
Along these lines I have a pet idea that a subset of IPv6 be geo-located, meaning your latitude, longitude, and possibly altitude are encoded in the IP address. This allows routing without the huge tables in the routers. Combined with the ability to verify that a packet came from its advertised location this is very powerful for security.
One way to verify the origin of data (email for example) is not to send it, but to send something akin to a URL (preferably better than that) so we have to at least be able to request the data from somewhere rather than have it sent to us anonymously.
Unfortunately being able to verify the source of data also enables end-to-end encryption fairly easily and nobody in power wants the public to anything like that...