Plasma's are still hands down the better product. I luckily bought my latest plasma in Nov '12. I went with a Panasonic Viera 65". LCD's and OLED need a good amount of calibration to bring the colors in line. The brightness makes the colors look deep but if you look at the same image on an OLED versus a Plasma you'll see that the colors are way off. Remember with LCD's and OLED's the tv interprets what it thinks the color should be. A plasma, since it's gas, is the true color. Often times plasma's are cheaper than LCD's and LED's. Their is honestly no reason to choose them.
Protip:
Purchase your tv the weekend before Black Friday. Sales for Stores are generally low that week which is a plus in your favor for haggling on price to start. Schedule delivery for that Saturday following Black Friday. Go back in on the evening of Black Friday and return the TV. The A/V department will not want to take a hit to their sales for the day so they will do whatever they can to keep the sale. That's how I got my $3,600 tv for $2,300.
Then why do top of the range BVM's use OLED LCD, if the colors aren't as accurate as plasma, or the picture isn't as good?
As far as I know, no PVM or BVMs are plasma. A lot of the time the screen quality depends on what brand it is, not just whether it's LCD or plasma.
You can usually compare the screens in the store, if you're worried about picture quality of the LCD vs plasma. Stores normally show things like computer animated movies on their TV's (ie, shows that make any screen look good), so you might want to take your own discs to the store.
The blue color on an OLED can apparently wear out over time, and the gas in a plasma eventually wears out.
EDIT: the resolution is 3840×2160
The resolution of 4K is 4 times the resolution of 1080p (double resolution on both horizontal and vertical = 2x x 2x= 4x). 1920 x 2= 3840, 1080 x 2= 2160.
1920 x 1080 = 2,073,600 pixels.
3840 x 2160 = 8,294,400 pixels (which is 2,073,600 x 4).
4K (where "K" represents a thousand) refers to the no. of pixels horizontally which is roughly 4000 (actually, 3840 for a 4K tv, or something slightly different for a 4K movie camera). Movie film can resolve at least 4K resolution (for 35mm film), or least 8K for 70mm film. So 8K will probably be about the limit for anything shot on analogue film. Digital movie cameras will eventually shoot films in higher resolutions than that, though. There are already movie cameras that can shoot in 8K.
1080p is sometimes known as 2K, as the no. of pixels horizontally is roughly 2000 (1920 to be exact, or maybe different for movie cameras that shoot in 2K).
Don't waste your money on 4K anything. 1080 is fine. Also, on smaller displays under 42" the difference between 720 and 1080 is a non-issue.
Definitely get 1080p if you get afford it. That way you're getting all the resolution that's on the blu-ray disc. 3D and 4K are more things that are nice to have (and the TVs that are available now will be superseded when 4K 3D OLED TVs are released). Most movies and tv content are not 4K or 3D. 40" is not too expensive if you haggle over the price (only take as much cash to the store as you're willing to spend- for example, only take $1000 in cash if it's a TV priced at $1200). In Australia a 40" Samsung 1080 3D LED TV is about $700-800, if you go to the right store.
