Okay man I will try to help you out. First of all, Plasma is a specific type of HD television. It was actually one of the first to see the larger sizes before LCD caught up to it. Here is another Fact.... Plasma has the best picture for the price. LCD/LED does not have better colors(contrast ratio) than a plasma. Where LCD/LED excels more than a Plasma is the brightness in a room. Lets say you watch TV in a bright room windows blinds open all the time, the LCD/LED will probably work better for you. Plasma is not as popular anymore because of early fears of burn in. Burn in is where if you run a static image on the screen for too long you could see a ghosted image on the plasma. This however on modern plasma is not a big deal, After the first few hundred hours a modern plasma is broken in and even if you somehow happen to have burn in you it will go away after a few hours.
Brands. The only brands you need to worry about with Plasma is Panasonic and Samsung. LG makes them, but they are not on the same level. Panasonic is the best, but this is their last year making them. Big box stores have sold the LED hype and plasma are selling nowhere the quantity of LED's.
Panasonic has 4 lines of Plasmas this year(they all come in multiple sizes). S60, ST60, VT60, ZT60. The S60 is the best value. with a 50inch starting at $699. NO LCD/LED in this price range will have a better picture. Don't lie to yourself. The actually tv might be a thinner, but when it comes to the picture it can't be beat in this price range. Next in line is the ST60 model which has even better quality but the downside is input lag. Only a problem if you are a hardcore gamer. You can google the model numbers for detailed reviews.
Okay in the LCD/LED game. Yes don't be confused a LED is just a LCD. instead of using CCFL backlight, they switched to LED lighting which allows for thinner bezels. Samsung, LG, Sony, Panasonic for the elite and on the cheaper side a Vizio are the only brands you need to worry about. The best option is a LED that offers local dimming. This allows specific LED lights to dim the panel and allow deeper and richer colors.
Not to judge you from your post though..... but TOO LONG DON'T READ just get a Vizio nikka. LOLOL

You won't know the difference.