andoo, welcome to the forum! "Value for money" is always a difficult thing to judge, since we all make different judgements as to the value of something. If choice per pound is your main driver, or the avoidance of an external dish, then I suspect you'll not go far wrong with cable. The problem I have is that I've seen much better picture quality on other people's Sky systems than I get on cable - much more difficult to quantify!
One thing I would say though is be careful that you compare like for like. You mention a monthly £10 charge for the honour, and I'm not sure if this in reference to HD services or PVR functionality (Sky+). I can't comment on ntl (who I didn't even know had launched an HD service?) but for Telewest the TVDrive service IS charged as an extra (£10 or £15 per month depending on which package you select), although this covers both the PVR and HD functions. Availability of HD is restricted as well, and given the difficulty I'm getting with SD bandwidth programmes I'd hate to think what HD would look like

Remember that cable and Sky also use different HD compression systems (MPEG2 for cable, MPEG4 for Sky as I recall) although whether this has any impact on quality I have no idea. Sorry to confuse you further!
Al