In the TV business the selling process starts back at the factory when manufacturers often set up each screen to look over bright and colorful in a retail store. In retail world the brightest set wins most sales, simple.
However, and this may seem like stating the obvious, but your living room is not a retail store. No annoying sales people, no Christmas music blaring out (at this time of year) but most importantly no harsh fluorescent lighting! So, if you want to see you brand new super shinny HDTV at anything like it's best you'll need to be setting the TV's "front panel controls" (Brightness, Contrast, Colour, Tint and Sharpness) to more realistic settings.
In the good old (bad old) days when colour TV was still in its infancy common advice was to set it "so skin tones look right". My answer is for who? Kate Moss, Wesley Snipes, Des O'Connor?. If we're going to get this right we need an approach with just a little bit more science.
To set your TV up for your own home needs a simple set of test patterns and about half an hour of your time. If you're panicking already because I mentioned "test patterns" don't. The patterns you need are already available as part of the setup section of many DVDs, particularly certain high budget animations. Just look out for something called a "THX Optimizer" in the disc menu, select and follow the instructions.
If you want to get more adventurous there are several other more advance options like the Digital Video Essentials disc published on DVD or BluRay disc. If you don't feel you want to get involved just buy from a good specialist retailer rather than a high street giant or mail order/internet supplier. Many will setup your TV as part of their install service and will smile nicely too! Some specialists will also offer something called "ISF".
ISF is short for the "Imaging Science Foundation" who publish a set of standards for TV calibration using a highly involved process that requires specialist test equipment and training. The results can be stunning and for a high performance set is worth every penny of the additional charge.
Whatever you do, make sure one way or another your TV is setup properly or it will never deliver the performance you paid for. Oh, and a properly setup TV usually draws less power so is better for the environment too!