I lowerest brightness to 35% and lowered contrast to around 35% from factory settings. I checked it out on some calibration sites and found it was great. I then compared it side by side to my Samsung 216BW which is one of the best TN panels and it looked far better than it. I spent hours calibrating the 216BW to be perfect and here this little Dell TN panel blew it away.
Also, though, keep in mind that the eyes adapt to certain settings in a relatively short period of time. This means that colors are quite subjective, in fact. If it looks good to you, then it looks good, just something to keep in mind.