Hi Shocket - you should listen to the latest AV podcast as it contains an explaination given by Telewest on the reason for the black bars. This is likely to be a problem for Sky HD too and has been the case for many football matches broadcast on ITV and the BBC for some time (as stated above). In these cases the footy is actually in 4:3 but the station is broadcasting in widescreen and so it adds the black borders to retain the correct aspect ratio (just as Telewest have done) and no matter what you do on your TV you can't remove them.
HD is a widescreen resolution and so anything transmitted in HD MUST be widescreen - this is why most (if not all) TV's do not allow you to change the aspect ratio of the screen when connected via HDMI, i.e. because it is intended for use by HD and so is usually fixed in Wide or 16:9 mode.
So if Telewest and Sky want to broadcast non-widescreen content in HD (usually by definition it will also be upscaled) then they have one simple decision to make - do they display it in its correct aspect ratio with black bars either side or do they attempt to stretch it. It's a numbers game and they can't please all of the people all of the time so they've stuck to the letter of the law and let the aspect ratio make the decision for them.
Now I, like you, preferred in the past to stretch these 4:3 images and I was more than happy with my old Toshiba's "Super Live" mode and my SONY's "Smart" mode but many TV's are crap at this, including my Samsung with its "Panoramic" mode, and the images look really squashed and distorted. Given the choice between the correct aspect ratio and the mild annoyance of black bars (which vanish as you sink into enjoying the show) and a distorted image - I think Telewest have made the right choice - and I'm assuming Sky will do the same. So this will not come down to a choice between platforms.
This problem will only ultimately right itself once everyone transmits in widescreen - which to be fair most now do.
In fact I don't think I've seen a single programme in 4:3 (with black borders left and right) since I switched over to the TVDrive last week
Cheers
KableMan