My vote is for not even worrying about it. IPv6's adaption rate is quite pathetic, even though we are nearing depletion of IPv4 addresses. Keep in mind that IPv4 can be tunneled over IPv6 (and vise versa), that hardware and systems that support IPv6 almost all support IPv4 too, and that many people don't even have IPv6 addresses. Eventually, it'll be nice. But in reality, unless you are a programmer of low-level networking (such as in routers, networking part of the OS, low-level enterprise network libraries, etc), you have many years before it is a concern.
That isn't to say that IPv6 support isn't a good thing, but its like 64-bit support - its nice to have, in some places its a great benefit, but for most applications it is just a lot of work with little (if any) benefit.
