It's not a standard lie, and no 1GB is not 2^30 Bytes (or as you put it: 1024x1024x1024). 1GB = 10^9 Bytes by SI standards, and the "metric system" before that. The hard drive manufactures are using the correct units. However, just about everyone else uses the 1GB = 2^30 Bytes, which the proper unit is GiB not GB.
They "get away with it" because they are correct. 1GB = 10^9 Bytes. Just because many people use the G prefix incorrectly does not mean that suddenly 1GM (GigaMeters) is now 2^30 Meters, that 1 GOHM is now 2^30 Ohms or that 1GB is now 2^30 Bytes. And, they won't change the numbers as it would go against standards.
Well that's 465GiB which is more or less 499,289,948,200 bytes which is just shy of 500GB, though in my TI-83+ rounded down a bit and the original data is rounded as well, so it's probably a little closer, maybe even a few bytes over 500GB.
Sorry if I seem somewhat attackish on this, I just bugs me to no end when people complain about the 1GB = 10^9 thing without actually thinking. More people should complain that Microsoft, the memory companies, the processor manufactures (that 6MB cache in your C2D is 6*2^20 Bytes not 6*10^6 Bytes), and others use 1GB = 2^30 which is incorrect.