There is a pretty decent hdmi cable on amazon for about £11 just now, apparently reduced from about £60. I got a few when I got my 3d tv. True that the signal being digital means jack for the transfer of data. But shielding can make a deifference depending on what other cables are in close proximity. But that one on amazon does the job.
As for the 3d tv debate. I didn't care a toss whether my tv had 3d or not. Instead, I wanted a "near" reference HD picture. Thus I went for the Panasonic VT30. Which happens to also be the best 3d tv on the market. I love it, but by no means watch most of my stuff in 3d. The HD picture is amazing though. Excellent blacks, and all that.
As said above, your probably somewhere around 5 years for 3d to get good, work the bugs out, and reduce in price. For me though, I change my tv every 5-6 years anyway, and my old set was 6 years old, so it was time for me to upgrade regardless. I personally wanted the best 2d picture, and got it.
The Samsung no doubt is the more aesthetically pleasing screen in your room. Love the look of it with no bezel, and super thin. But I personally preffered the cleaner picture on the Panasonic.
But I will say this for 3d movies, as I do currently own MOST of then on Blu Ray. A Turtles Tale has the best 3d effects I have seen thus far. Its a kids film, and not really a very good one either, but the 3D is the best I have seen thus far.