http://www.rr.com/rdrun/
Roadrunner in the US have just increased their cable ISP service to 5Mbs, being as they are on a similar technology platform it would seem there is scope to remain a step ahead for the forseeable future.
Of course when the limits of twisted pair ADSL and coax are reached, NTL/TW will find a find a Fibre to the Home roll out for LAN speed WAN easier as fibre penetrates further into their network than BT.