As I seem to have a similar line connection to you it may help your decision if I give you some of my line results.
Ping Result
Speed Result
My router is a Netgear DG834GT
Firmware Version V1.02.16 - DGTeam Rev. 0848
Router Stats
My line distance is approx 4.2 Km from the exchange. My ping before was similar to yours now at around 37-40ms, but after asking to be moved to fastpath (switching interleaving off) I now get around 18-20ms. I play a bit of Bad Company 2 onlline currently and on UK servers rarely see people getting lower pings than me.
One thing to note is that if telephone support is necessary for you then TT is absolutely not worth it, but their talktalkmembers forum is pretty efficient.