I have 5 machines (one of them dual-booting) in the house, 4 of which are used for gaming with Steam on different accounts. 2 games consoles. Windows updates x 5 + OS X updates * 1 + Netflix + Steam + Bittorrent (mostly legitimately free music from various chiptune artists out there, occasionally also games from the Humble Indie Bundles, software from Sourceforge, or films/tv from the likes of Vodo) + occasional commercial software purchases/trials + regular Linux ISO downloads + Youtube/Vimeo + emusic account = a %^&*load of network traffic.
I pay for the top-level service from Virgin because I know that's what my usage pattern needs. Until these ridiculous new terms were introduced, that was fine. Now I'm in a situation where even if I can do it during what they call daytime hours, buying one new game on Steam and installing it puts me over my usage limit (every big new release I've bought since Portal 2 has been a 10GB+ download, and that's before we start about downloads on different accounts - and no I couldn't be arsed with manually copying files between machines, that's why I was paying for the fat pipe from Virgin).
If they don't understand why an uber-fast connection with stupid "fair use" limits is pointless, $%^& 'em. Why on earth would I want 120MBit broadband if the data caps are such that I'll barely have started using it before I get throttled?