power cord affects on video?

Don't know about TV sets but I put $13 14 gauge shielded power cord on the computer and couldn't believe my eyes - everything looked so much better on the monitor. Sound from the computer was also better. Then I put second power cord on the monitor - no difference. Then I compared $150 audiophile power cord and that $13 power cord - no difference, but my computer monitor is probably 15 years old. More than enough for me, though.

Based on my experience, a good quality power cord would definitely improve image quality. Be aware, what sort of AC plug is used.

Rhodium or Silver AC plugs (with better emphasis on high frequency!) will surly enhance the details, resolution, 3D effect in term of layers of scenes in image as well as vividness, sharpness of edges in scenes. Sometimes it becomes weird  (!!) where in movies when they use those green screen to project other background!!, with layering of scenes you could easily observe that filming has been done in a studio!?

This is because, all these mentioned terms rely on high frequencies of video signal. Low frequency of video consist of definition of contours. 

You don't need to spend too much money on these PCs. You could make your own DIY power cord (~$80, like Neotech PC Hybrid mkIII) with cheap AC plugs like Sonarquest Rhodium or Silver (~$25).

hope that would help...

MY early adapter $4000 (on sale) 42" Sony Plasma picture improved with a $50 Pangea AC14SE back when I first put an aftermarket cord on it. The color got brighter, the grain decreased.                
Currently I have a Pangea AC14SE mk2 signature (2m $80) on the plasma from my Furman REF 20i power conditioner.                       
Worthwhile improvement.                
I would say for a TV the law of 'diminishing returns' hit pretty fast. I would never spend more than $100 for a TV powercord.               
(and one reason I stick with Pangea.. audio like video, diminishing returns. How far into the fractal zoom you think is worthwhile?? For me it stopped at $450 a pop. Most around the $100/$150 mark.

How do you know it’s the law of diminishing returns? Hint: You don’t. In audio the only constraints are the ones in your head. I suspect yours is a case of penny wise, pound foolish. No offense.

Goeff is 100% correct on penny wise pound foolish. I scrimp on many things, Just so I can then burn money like a fool on others. I rent cheap, eat cheap, dress cheap, and then own a good 'Hot Hatch' car, and a great stereo. But sorry Geoff is not correct about a second part part, yes I do fully know the law of diminishing returns in the audio arena. I would say I am somewhat far up the price vs return on value ladder. (but only in a mid fi sort of way.. My one true Hi End expenditure, replacing 17 AC Duplex with Furutech GTX went OK, But that was just a one time momentary madness)And finally constraints.. In my head? No, they are on my bank balance.100% the bank balance.