I'm using utorrent, and it seems to crash my internet connection. I can't seem to force it to drop, but when it does, rebooting my Motorola Surfboard SB4200 will bring it right back up. Sometimes it dies after just half an hour of having utorrent up, sometimes I can leave it up for more than 24 hours with no problems.
I've double checked the port forwarding in my router (cheap dynex wireless), and I've tweaked utorrent to reduce the number of simultaneous connections but none of that seems to have helped. The fact that it's always power cycling the surfboard that brings the connection back up makes me think that it's a problem with the modem, but maybe I'm missing something.