here is a good start http://forums.cnet.com/7723-19410_102-584819/vizio-e420i-a1-picture-settings/
here is a c net review http://reviews.cnet.com/flat-panel-tvs/vizio-e420i-a1/4505-6482_7-35508623.html?tag=posts;msg5420445
do these numbers this in custom or preference mode whichever your set has set keeping in mind cnet and most other sites calibrate for viewing in a dimly lit room to many variables for them to do otherwise.
screw the backlight in the Picture settings menu up to about 80 for normal viewing in a normally lit room or daylight that should get you close make sure to set as below
-Advanced Picture submenu
Noise Reduction: Off
MPEG NR: Off
Color Enhancement: Off
Adaptive Luma: Off
Film Mode: Auto : Note I would try this in off mode see how you like it?
Smart Dimming: Off
Ambient Light sensor: Off