My TV is a CRT in old format. I’m ready to get a new widescreen digital. What do I need to know? How do I get a good one? What are the performance specs and what do they mean?
Plasma vs LCD?
1080p = ?
refresh rate?
HD?
Help the clueless.
www.blackfriday.info. 
You might want to read the television buying guide at CNET, located here. It should answer most of your questions.
In a fast nutshell
1080p isn’t used for OTA (over the air broadcasting) but is useful for Blu Ray. Eventually 1080p wil be used as soon as someone figures out how to do it economically.
1080i stands for interlace, while 720p is progressive and refers to the scan. In general 720p is better for sports and TV shows requiring a lot of action. So if you’re a football nut, you’d be better off with a native resolution of 720p.
Nature shows which don’t have a lot of action look better with 1080i.
But even this is subjective to the person viewing it.
Only OTA broadcasting delivers real HD anyway. Cable, Dishes, FIOS (Verizon, ATT U-Verse) compress vids before sending then they get recompressed. And there IS a difference between OTA HD and Cable HD. And if I can notice it, it’s noticable.
As for set, LED, Plasma, whatever, this is totally up to you and you need to look at it. It also depends where you put the TV, what’s the lighting of the room, etc. Also look at power costs between the types 'cause this varies.
As for HD, if you get a screen less than 30" HD is not needed. The human eye can preceive it at screens less than 30" so it’s a waste of your money if you get a small HD screen.
You could read on for hours, and there’s someone who will always debate what’s is better.
Find you what you basically use your TV for, (Sitcoms, sports, dvds) then figure out where the TV is going, what’s the lighting in the room, how far you’ll sit from the TV and then base your choices on that.
There’s no right or wrong and most certainly in the next year or two people will invent better ways and your TV will be outdated, but that is technology isn’t it
That’s not really true. A small HD screen is worthwhile if you sit close to it (you may not use it for a typical living room setup but might have it next to your bed for instance.) The further away you are from the TV the bigger it needs to be for you to get any benefits from the higher resolution.
Rule 1: Buy the biggest set that will fit in the space you have available, even if you can’t afford it.
In the history of wide screen TVs, the following sentence has never been spoken: “I wish I’d bought a smaller set.”
Whatever you buy will look better than what you have now. LCD is usually cheaper than Plasma, but for the longest time, Plasma TVs had blacker blacks and could be seen at a bigger angle from the side. This is really no longer the case.
It is possible to get too big a TV screen. The standard I’ve always heard is to get a screen about 1/3 the size you sit away from it. For example, if you sit about eight feet away, you should have a screen that’s about 32" diagonally. However, some sites have claimed that this ratio is too big. Some sites claim you should divide by 2.5 and others claim you should divide by 2. I guess it depends how much of a TV watcher you are. If your old TV was a 12" black and white model with a coat hanger for an antenna, you probably would be fine dividing the distance by 3. If you bought one of those 6’ projection screen TVs, you probably want to divide the distance by 2.
Right now, all broadcast is 720 and only BlueRay disks are shot in 1080 format. Again, whatever you get will look better than what you have now, so its okay to be cheap.
Another option: Forget about buying a TV. Instead, get a PC with a really big monitor. Then, you have a media center. Not only can you watch anything being broadcasted, but you can watch all the programs that are on the Internet. Comedy Central, CurrentTV, NBC, Fox, and I believe ABC all put their shows on Hulu.com. Not only that, but many of the classic shows are also on Hulu. I love watching the Alfred Hitchcock Hour. CBS has their own website for their shows and has all the original StarTrek and Hawaii Five’O (Book him, Spock!). You can also have it tape shows, so you can watch them later like you can with Tivo. You can also watch content from iTunes, YouTube, and Netflix.
We originally got a cheap Dell and tried it with Vista (awful), then we downloaded Linux (not too successful). However, we now upgraded to Windows 7, and the Windows 7 Media Manager works pretty darn well. We have a 32" monitor, but you have to understand that our old TV was only 19", so it seems plenty big.
And one more thing you have to consider: Do you get broadcast or cable? If you get broadcast, and your picture has lots of snow in it, you won’t be able to see digital broadcasts. Digital broadcasts are beautifully clear (no ghosts, etc.) but digital broadcasts don’t degrade very well. You might have to upgrade your antenna.
Take a look at Antenna Web and see what size of antenna you need in order to receive a good picture. They’ll take you step by step through the process. You can also go to theFCC’s DTV Reception Maps.
Then go to Denny’s TV Antenna Service to help you pick out a new antenna. Denny is one of the few honest antenna services on the Internet. For example, he freely admits that there is no such thing as a HDTV antenna. An antenna doesn’t care what type of signal its receiving, it just cares about the frequency of that signal. Too many places try to sell you a premium digital antenna.
Anyway, don’t go overboard. Just remember whatever TV you get will have a better picture than what you have now.