The IPv4 pool runs out in about one year. At least that is the estimation now ;) I have done some research [webmasterworld.com] on IPv6 a few months ago but haven't finished it yet because none of my hosting companies has been able until now to provide me a native IPv6 address block. Except for the main Internet backbone, IPv6 availability is still a problem in a large part of the Internet network. And another problem is that a number of home routers are not able to process IPv6 addresses correctly, causing websites with both IPv4 and IPv6 address references to become unavailable [webmasterworld.com] for those users.
Expect for the joy of experimenting with it, IPv6 is not a good choice yet if you have a major website which you depend on.