So i've had a promotion at work and i'm treating myself to a new t.v (yay) and i've heard some very good things about led lit lcd tv's, the one i've got in mind is the samsung ue46b 7020, anybody got any opinions? 

Not sure tbh, I was looking into it about a month ago but not much about them yet, all I do know is some models do have problems with LEDS stopping working which then affects the screen.

that's the one big issue i have with them tbh although i'm hoping it's been ironed out by now since sony bought the 1st led commercial screen out in 2004

Well, everyone that ask me I suggest to buy an Plasma TV. LCD TV have problems with motion resolution,color gamut, black level and so on. A LED TV is still an LCD TV with led back light, the motion resolution problems, black levels, color gamut and response time is still there. Don't get me wrong by saying, LCD tv are pretty good and there is models and models of tvs, but in general plasmas are better and i already compared an LED TV with an LCD TV and there was a difference in image quality, but nothing to justify the difference of price.

I recommend you 2 TVs that are the best for gaming nowadays: Sony LCD W550 and Panasonic Plasma G10 .

I'm still not sure about plasma because of the cost to run one although i agree that the picture quality is amazing on just about all midrange plasmas i've seen

edit- you've got me intrigued about that panasonic plasma screen now, looks amazing and so much cheaper too, is the running cost really that bad with a plasma?

Well, it have a NeoPDP display. I don't know what you mean by running cost, there is a good review to show how good the TV is. I think if you don't have problems with Green Ghost Plasma is always the best option. 

http://www.hdtvtest.co.uk/news/panasonic-tx-p42g10-tx-p42g10b-20090415146.htm                                            

This is an UK review, the american one is pretty similar, but have the THX mode that make image look even better. I'm buying one 50 inch one of this for me once it's realesed in Brazil.

Still kinda young tech, at least the ones available for retail. They're too expensive yet imo and not as reliable as regular LCD's just yet.
The specs are better but to me this is like buying that graphics card that is 15% better for twice the price; not worth it.

I wish OLED technology was cheaper and supported larger screens.. that would be the best technology to have in TVs.

I returned my Plasma and got a LCD instead, SOOOO happy I did, a lot of people are still living in the past regarding Plasma vs LCD, recently LCD's have matched plasmas and some even surpass them,

My LCD (1080P 120hz) has no issues at all with ghosting or black levels, the picture is absolutely stunning with a 0.3ms response time and no lag at all, it puts a lot of plasmas to shame including my mum and dads sony plasma and my sisters panasonic plasma, it has more features than most plasmas out there (including 115 picture settings lol) and you don't get the plasma screen burn-in issues you get with most plasma screens (still a problem on todays sets although not as bad as they used to be), why would I want a plasma tv where I would have to worry about leaving a game paused for an hour or more (i do this a lot) getting screen burn? no worries with LCD.

LCD and Plasmas both have pros and cons but LCD's are moving along at such a fast pace, add to that most of the plasma tv makers are now moving to LCD instead (pioneer, samsung, sony etc) and you can see which one will be here in the future.

I sadly have to respond LCD. But be sure of one thing, plasma will be out of the market not because of techonology issues, but for market pressure made buy negative marketing that plasma technology received over the years. Burn screen don't happen anymore, just if you let the image there for 24 hours or so, if it happens with normal use warranty is there. 120hz lcd are pretty good too, but still having the problem with irreal colors and motion resolution. People tend to prefer LCD livid and brightful colors while I like Plasma real and natural. Plasma is still the choice for videophilies since the best display avalaible is still Pioneer Kuro and Panasonic 65VX100U. I'm getting a plasma as fast as I can because I recognize it tendency to disappear from mass-market and stay just in niche market with astronomic prices. I hope Panasonic NeoPDP could change people mind about plasma tvs, and at least consider them as possible buying.

I really get sad in stores when you ask to look plasma tv the seller says"This technology is dead, the best you can have is LCD".