I've good a reasonably good grasp of TCP/UDP/IP (certainly better than 99.99%) of the population planet has). But despite many hours of trying I could not come up with a workable QoS setup.

The best I came up with was with everything throttled back to 25% of the upstream bandwidth, but with you only start with 800k that wasn't exactly workable

(and even then VOIP used to regularly get hit with a lack of upsteam bandwidth)

Though I'm not sure QoS on my Tomato router was working quite as it was supposed to, so that probably didn't help.

Instead now I have my CrashPlan backup throttled (within the service itself) to 45% and BitTorrent throttled to 30% (again within the BT app), leaving some space for SMTP/DNS/HTTP even when BT and CP are running at full pelt (which isn't that often). And I have a separate line for all our laptops/desktops/iPads/iPhones/Apple TV/set top box/etc

Works much better than I was able to achieve with QoS.