Regarding bittorrent, I'm wondering if that's not just as much the fault of crappy NAT modems. Around here everyone gets a Zyxel, and bittorrent totally chokes it periodically. The hash table used for NAT grows, the CPU can't handle it, to the point you can't even log in to the modem, and new TCP sessions get dropped until the NAT clears out the old TCP connections. (With a proper network device, this shouldn't be an issue, but it's one I see all the time with the cheap modems we get from the ISPs)