i'm pretty much in the same boat. I dont think its anything to do directly with 10Mbit / upstreams or torrents.
I've been with NTL since the very start of broadband and we used to get a nice 512k solid and 15-30 pings to gameservers. Since broadband has become more affordable and readily available certain local area hotspots have become rather congested. With the introduction of faster speeds and many more connections we are seeing these problems with slow speeds and bad pings popping up all over the country.
NTL have done well with the UBR balancing scripts which try to AUTO sort customers so the UBR's are running smoothly. However we just need a little more capacity in certain areas to maintain happy customers. My UBR's are so busy on certain interfaces that life is just a constant battle with pings and packet loss due to congested upstreams. I like to play games and thats pretty much all i do with my broadband but i get disconnected from game servers because i lag out (cannot maintain a stable data flow and pings fluctuate into the 1000's). Although i do get lucky somtimes when they rebalance and i get moved to a quieter upstream.
I know some other people on NTL locally and they are connected to another card on the UBR and all is fine for them. I dont think this problem will get any better until NTL provide a little more capacity for the very busy areas. Thing is they have tonnes of bandwidth to play with its the local UBR's that seem to need a little help. Its a shame that they set their operating standards to 80 or 85% saturation because by about 70 / 75 with the fluctuations the service is just degraded and broadband becomes tedious for certain things.
The first step i say is more running regular balancing scripts like every day or so by default and a physical re-segmentation for heavily congested areas. Traffic shapping to give P2P ports lowest priority would also be nice but that will never happen.
Do NTL still have p2p cache