What needs to happen for IPv6 to take off? CloudFlare is doing a lot by allowing automatic IPv6 for many websites - it makes it very easy to get a foothold in IPv6.
1. Consumer grade routing hardware that always supports ipv6 out of the box.
2. ISPs transitioning into supplying both an ipv4 and ipv6 address to households.
3. Major network backbone services (google, amazon, etc) transition to both ipv4 and ipv6.
4. Once a majority of the critical network infrastructure is available on both, ISPs need to start dropping ipv4 addresses from customers, preferrably from new customers.
5. Slowly depreciate ipv4 by using a ISP provided ipv4 tunnel service for a while for those that still need to access the ipv4 web.
Basically, it requires most of the work be done on the backs of ISPs. In the US at least, the ISP business is an oligopoly of cable tv and Hollywood and will resist ipv6 because it enables more peer to peer trafficking and open communication over the Internet.
I actually think that the content hosting folks are behind the curve here. Amazon is one of the biggest hold-outs; their IPv6 rollout has thus far been a total joke. No IPv6 for Cloudfront? No IPv6 glue for Route53 authoritative nameservers? No IPv6 on VPC, barely on EC2 at all, etc., etc. From what I've heard, the management at Amazon doesn't really care about the network behind their infrastructure; instead of investing in building a backbone that could do a better job supporting this kind of stuff -- and all kinds of inter-region applications which would be useful -- they want pretend the network doesn't exist and that nothing needs to change. It's too bad. I think we'd see more IPv6 usage if Amazon would get their act together.
I switched to a manual tunnel from HE (tunnelbroker.net). I confirmed this worked, that my Apple devices behind the Airport Express all got IPv6 addresses and so forth, and that the performance was decent.
Experience in hand, I then tore it all down, since I couldn't think of a good reason why I really needed IPv6 at home. :-)