Thanks for the replies.
Regarding your suggestion rustberger, unfortunately that piece of functionality is not available on my particular instance of WMC. A bit of googling suggests it may have been removed going from Vista to Windows 7, but I cannot find any conslusive info.

Thanks 3D Jed for the link to the HD card, looks good. Part of me is worried that maybe my graphics card (1024Mb NVIDIA GForce 220) is not up to the job though, and hence I may be wasting my money - I am puzzled by the fact that there is a *huge* difference in quality between live broadcast, and recorded/streamed over PS3 versions of the same program. Makes me wonder if my TV Tuner card (Hauppauge HVR-1000) or Graphics card is letting the side down.
Thanks for all the help, and happy new year.
Martin.