Go with what your eyes see ....
If you really need to do an actual calibration, get a disc or hire someoone to come out and do it, but ultimatly it's going to come down to what YOU see.
You can get the best guy out there or the best disc out there and have it all calibrated and find out that it's nothing close to what you want to see or the way you like your set up.
What would you do then, say this is the way it should be, even if it doesn't look right to you , or are you going to set it up for what looks right to you ?
Everybody sees differently.
Yes they will help in pointing out different things to look for, as far as black and white levels, contrast and sharpness, but eventually it has to come down to what you see.
I could come over and set it up perfectly to what a disc says or what I feel is correct and you may think it's great or garbage ....
Jimbo