no problems here
I've had an xbox 360, PS3 and PC, been with virgin media for years and never had any problems.
If it was a VM issue wouldn't it be the same for all games on all platforms not just black ops? there would obviously be a lot more outrage if it was a VM issue.
fire up an MMORPG, play on US servers and start a PVP match, no issues at all, same with any FPS, while I was typing this I thought id give modern warfare 2 a test and theres no lag!!
I commend VM for taking the time and wasting resources looking into the issue.