One of the comments that I hear a lot (and I am sure to receive on this site) is "But I don't need IPv6 for that! I can do that in IPv4!"
It is true that a lot of what we can do in v6 we can do in v4 as well. That's because v6 is based on v4 and needs to accomplish all the same tasks; they are both just Layer 3 routed protocols at their heart. In terms of basic functionality, there isn't a lot that IPv6 can change/introduce that wouldn't break existing networks.
Instead, what v6 offers is the ability to simplify and standardize a lot of the things that were difficult in v4. It makes hosts easier to configure (but v4 can do that!), it makes security easier to setup (but v4 has security!), it makes end-to-end connectivity easier to establish (but v4 can kind of do end to end if the specific application is designed to work around NAT!)
For example, using IPv4, write an application that allows my machine to connect to your machine through a NAT on each end so that we can play head to head games. Um, well, that's......hard. In v6, it's easy. It just works.
How about this: using v4, write an application that allows my Windows machine to setup a session to your Linux machine so that we can perform host authentication and encrypt data. Oh, and no, I don't have SSH on my box. Umm...well, you could...yeah. With v6, it just works.
Anytime an enterprise can simplify operations, anytime device setup can be simplifed, anytime we can remove complexity from the most number of users, IT finds benefit from that. That is what IPv6 is all about.
So, can you do that with IPv4? Quite possibly. But with IPv6 I can do it for less money, in less time, while using standardized, proven security.
One more example. I only have an IPv4 address in my ADSL and of course it is NATed. Paying for more is a huge cost. Instead, I use IPv6 and then I have a /48, which means 65.535 subnets of 2^64 each. Now I've in my home lots of IPv6 devices, such IPv6 cameras, and all kind of gadgets. I can control all my home automation remotelly, I can feed my pets, open the blinds to see them with the cameras, etc.
It is true that I could do that with IPv4, but with a huge extra cost or writing an application that traverse the NAT; once more is a matter of cost.
IPv6 brings simplicity back to the networks, and thus, makes things just work very inexpensively.