Inphinity:michaelmurfy: those who download over 500gb are either doing something dodgy or should be on a dedicated bandwidth plan (depending on what they're actually doing)
Steam :P
Seriously? I do not beleive that you can get through 500GB of content in a month and actually use it. You would have to be downloading dozens or hundreds of steam games every month to get up to that level, and there is no way you have time to play even a small fraction of them.
besides which, if you can afford that many games, even at steam sale prices, then you probably aren't worried about spending an extra 50c per GB for the extra data.