After pouring over the settings in this thread I still wasn't satisfied with the color response from the TC-55LE54. Reds were consistently displaying as magenta and this was really bothering me. I also have a TH-46PZ85U which has great color response so I wanted to match the colors between the two displays.
What follows are the settings I ended up with. These are by no means scientific or calibrated professionally but rather the result of a few hours of trial and error in order to get a more accurate red display and overall color balance. This were calibrated watching the Australian Open so the content is very bright (full summer sunshine) thus they may not be appropriate for your content.
Picture Mode: Standard
Back light: +92
Tint: +3 (needed to de-magentaize the reds)
Color temp.: Warm (needed to de-magentaize the reds)
Color mgmt.: Off
A.I. picture: Off
Video NR: Off
Block NR: Off
Mosquito NR: Off
Motion Picture Setting: Off (I hate the SOE)
Black level: light
There is still a slight magenta tinge to the reds but this is much better than before. Aside from the red/magenta issue and that Costco listed this with a 120kHz refresh rate (argh) I'm pretty happy with this TV and it probably would be hard to beat at the price.
That said, my Dad just got a LG 55LA6800 which I helped him set up and configure and the picture is incredible. For my next TV I will definitely consider LG along with another Viera.