Additionally, and to my experience with HD, the most important is to have the set
Calibrated after a break in period of about 100 -150 hours of use.
Being a total novice, I listened to the pitch and demonstration by the salesman when we decided to invest in a new plasma, HD capable TV here in the U.S.
The service costs about $150 (US) but it's nearly amazing how much improvement is experienced when it's done. One can also do it themselves with the use of kits to assist. Here, it's called calibration but may be a different technical term in the U.K. Check it out... Here's one source of information:
http://www.nytimes.com/2008/04/10/technology/personaltech/10basics.html?_r=0