It's something like a /48 for each second m^2 of Earth's land surface. Single addresses are not a useful metric, as IPv6 works a lot more with prefixes (groups of addresses, to simplify management and allow things like auto-configuration). The smallest prefix that you would assign to a VLAN with auto-configuration is /64. So /48 (or 65 536 subnets) in IPv6 would be the equivalent of /16 (like 192.168.X.X but global unicast) in IPv4. That is what normal businesses usually get. Home customers should get a /56 of IPv6, that still leaves space for 256 subnets with basically unlimited hosts in them. Not too bad I think.
