While I look forward to that future, realistically nvm ram is going to be at least as pricey as ssds or volatile ram, which means that a more likely in between approach that tries To minimize the amortized io between fast nvm (our ram replacement) and cheap and relatively slow nvm (hd or ssd).
If it would cost as SSDs do, it's pretty simple then: you mount NVM as /, and /var & /srv are still on disk. All your programs lose start-up time and most of swapping.
If it would cost more, you can use it as a persistent block cache (that survives reboot), but it doesn't make much economic sense since nobody is willing to pay money for just faster start-up and warm-up after reboot. If you have 8G of NVM, you could just read 8G off disk in something like 30 sec and be settled with regular RAM.
