I suffered with input lag issue on this TV for quite a while, looked through all the forums for solutions and all that but I finally figured out a way to remove all the input lag. I can't notice any at all and I play a lot of first person shooters. I have no idea if any of these steps are redundant or not but I know this series of steps does remove all the input lag so that the frames look identical on my monitor as well as my tv in duplicate display mode.. Also I applied these settings to my xbox 360 display settings and really ripped up a few matches on the weekend much better than I've ever played
1. First, Set the input label to game ( PC may work also )
2. Go to Home->Setup->Picture and set the mode to Expert 1, turn basically everything off (noise reduction, 'super mpeg blah blah' ) turn the backlight back up to 80 or 100 so it's not as dim, Ensure TruMotion and LED dimming is OFF
3. Exit that menu, and use the button on the remove at the top that says AV mode and set it to 'game' (this may be the redundant part but I think there is some inheritence regarding the stuff in expert 1 )
4. Now for the key to making it all work, Change the input to something else all together, then change it back to the Game Input you want, it's almost like you have to switch inputs for the changes on processing to really get applied.
I wasted many hours playing with settings but not changing inputs back and forth so I wasn't 'really' seeing the changes and assumed it wasn't working, Lame! Anyway post back if it works for you.
A little extra : Regarding the 3d on the TV you can really reduce ghosting quite a bit by setting the sharpness value to around 34. Also by using the RealD polarized 3d glasses from the theatre, they seem to work alot better than the ones you get from LG regarding ghosting