If you can put a bandwidth limit on services, do so during peak hours only, then for over downloaders, throttle by user, not by service. It's more fair, because it's the nature of most routers to proportion bandwidth by number of open tcp connections, not by IP address. The same thing happens to most commercial and enterprise class routers, not just the little Linksys paperweight that someone may have at home. This is one reason to add a specific per-address bandwidth restriction in a coffee shop. The nature of the system is that the single pig whose bit torrent program opens 200 connections at once gets as much bandwidth on the system as everyone else combined who is just reading the news and checking their stock quotes. Essentially what you do is offer a guaranteed speed of half a megabit per second, and a max of 6Mbps (example) and as soon as the user passes a 50GB peak hours quota, cut him down to 1Mbps (or even to the 500kbps figure) until 9PM. This would probably solve the problem for the most part. It will force people to reevaluate the times they choose for their large downloads (unless they have to be done at a certain time), encourage those who really should be paying for a larger package to do so, and not degrade specific services. Bandwidth shaping systems are really problematic. It's best to just limit traffic by user.

Wow. I'm too tired to pay attention to the formatting too.

Sorry.