Because my flat has no TV aerial at all, so I'm dependent on NTL to get any TV service whatsoever, and due to their annoying all-or-nothing attitude to their various services, I can't have their cable TV without also having their phone, at which point it's easier to go with their cable broadband than ADSL.

Don't think it isn't tempting in spite of that though! I don't watch that much TV; my television set is more usually acting as an output device for game consoles or DVD/video players. I may yet say pfah to the whole boiling and go ADSL.

If NTL still supply analogue cable in your area, it's possible to just buy the appropriate adaptor from Maplins and connect the wall-box socket directly to your TV RF input, regardless of whether you're paying NTL or not. This is what I do (because my flat too has no TV aerial)...