The other problem is that to get the colors right, you ought to have a color filter thing. Retail calibration discs usually come with such filters.
avsforum.com also has threads for each TV (in the display device section, usually called "TV x - settings and tweak thread" or something) where users share the settings they have after calibrating. All TV's are different so there's not an exact consensus, but usually people agree on a range of values and that may be "good enough" for you. It's certainly a good place to start.