I'm on NTL/Virgin as well and don't have throttling problems even running p2p/torrent software. The trick is to avoid the publicised times of 4pm to 9pm and you can download/upload as much as you want at full speed
Between those times the basic package is throttled for 5 hours when you reach the 300mb limit, but the next package up gives you 800mb before it's throttled which is why they wanted you to upgrade. If you can download/upload the database late evening or in the morning you should never have any problem.
I complained when Virgin took over about losing Sky One, even though I never watched it. Now on the XL TV package, phone and 4mb broadband for £30 a month.
