You are going to need some device to connect to the ISP's network. They are presumably going to provide the same functionality they provide now (why wouldn't they?)
If you are knowledgable enough to build your own, then you could do that... but you could do that today, and you could buy your own block of IPv4 addresses if you wanted to, and ask the ISP to route traffic to your own homemade router, and allow whatever lack of security you felt like having. I've already got 5 IP addresses because I bought 5 from my ISP. With IPv6 I could probably buy something more like a few thousand, but it's the same principle.
The only real difference in IPv6 is that the hack that maps one set of IP addresses to another set of IP addresses isn't necessary (note that you're still allowed, if you want, to do some sort of NAT mapping, if you want to... but it's unlikely that anyone will bother.) Everything else is the same as it used to be.
I guess my point is, IPv6 is going to be a good thing because it will remove a lot of complexity involved in the current set of hacks, and will also make Internet access a lot more possible for other countries, and we don't need people generating panic where it's totally unjustified. Next thing you know we will have Congressional hearings and a bunch of Democratic congressman demogoguing it and passing legislation regulating how engineers are allowed to design networking software.
Right now, a packet can be routed to an ISP using the first 16-24 (more or less) bits of the IP address. Each ISP, regardless of how many hosts it serves, will only have a few (often only one) continuous range of addresses it serves.
If addresses are disconnected from routing, how is any packet supposed to get where it's going? The only way I can see that working is if there's a "routeserver" that acts like a nameserver but tells a client the sequence of hosts it should use to reach a particular IP address; routeservers would have to be even bigger than nameservers (since many machines have IP addresses but not top-level domain names) and the 128-bit "address" would be no more useful for hardware routing than a hostname.