If you have a good source (whether plasma, lcd or projector) you would be an absolute mug not to have it calibrated professionally. The proper accurate measuring gear will cost more than the TV.
I spent months trying to sort out my plasma, a 60" Pioneer Kuro, by using discs etc and thought it was ok. Eventually I managed to find a ISF certified technician to come and do the calibration properly. It took hours for him to do but now I have ISF DAY and ISF NIGHT settings in addition to the usual USER, MOVIE etc.
It now looks so much more natural than before and if you flick back to my old settings the colours are all pink. The day settings are for max light output before the screen starts to clip the white with the black pushed up so you can see shadow details in day light. The night settings are set to be as black as low as possible without crushing the shadow details, with the white being dialled back as not to cause eye strain during nighttime viewing. These settings have also been adjusted for correct colours, gamma and grey scale.
It cost around $250 (can't exactly remember as it was 2-3 yrs ago.) As a percentage of the screen price this is less than 5% and for the improvement was an absolute bargain.