well just leave them at 125 priority, or limit the number of connections on the torrent client, you can try as well as manually setting the upload rate in the gatway to something a little less than your actually upload. Make sure you have dynamic fragmentation left turned on. Other than that it's trial and error. Torrents will always hog bandwidth and the only solution is to limit their bandwidth on the torrent client, get a separate internet connection or dont use it at all.
What I did was just give all clients browsing priority and left everything else. so ports 80, 443, 53 all had priority over everthing else. I set it to,
well i forget. 32.

in terms of games, kyou are going to have to find out each and every port used. This image is very basic. Local port range I left all ports open because well, windows likes to use random ports to connect outward. You can see this by going to router logs you will find your ip address with a port connected to an ip address on port 80. IE: 192.168.0.187:3462 > 24.112.231.5:80
So. local port range leave wide open. remote port is the actual port your connecting on.ie: 80, 880, 21 etc.
The Francis computer i gave the lowest of low priority because I was always frustrated with his torrents killing the bandwith to the point where the router was so saturated it quit working.
Sorry if i made it a little confusing, i'm not really payign attention to what im writing, but in my head it sounds ok.
ttfn.