HDTV stands for high definition television, which means that the quality of the picture coming from the television is of better quality than a regular standard television.
I do not own any 50 inch HD televisions, however I am considering buying a Sony Bravia HD television of that size or a Samsung LED television (greater than 50").
They don't exist, sadly. If you want a decent HD TV it will cost over $700. Check eBay or craigslist.org and buy used ?
All PS3 can be HD when they are connected correctly to an HDTV. They can also be 480i to match that kind of TV and 720P for those style HDTVs
You can buy cheap or inexpensive HDTVs at Walmart or Target. The price ranges from $300 to over $1000 so it depends on what you are looking for and how big of a tv you want.
The PS3 was designed for HDTVs and only works on a standard 480i TV. It does not give you the performance of the PS3 on a HDTV with 1080p and now the top 3D HDTVs offer the best video capability. That's why the is now an optional 3D display screen for the PS3 at $500
According to cnet.com which is linked here http://reviews.cnet.com/best-hdtvs/ The best on the market at this time is the Panasonic TC-PVT30 series, but it is very expensive.
HDMI is a connection plug on the back of HDTVs to allow other devices to be connected to the HDTV. Before HDMI they used S Video and Component connections to connect devices
In context of television definitions, with HD standing for high definition, SD stands for standard definition - meaning all non-HD televisions signals.
CNET has some of the best reviews for HDTVs. They will have top brands and will categorize and compare tvs based on price ranges and features. They run HD TVs through a series of tests, and then score them based on these tests as well as have the reviewer use the tv to gain first hand experience with it. These reviews are unbiased and extensive.
The efficiency of LED HDTVs are that the light source will never go out or fade like LCD televisions. They do not need replacing and the TV will be as bright as ever.
The best HDTVs are SONY.
High quality HDTVs are usually not hceap. You should look into off brands like Coby. If you don't want it stolen, do not buy name brands. Another option for security is to keep a lock in the mount.