We refer to a TV oder computer monitor as a widescreen TV when it is wider than the classic 4:3 format of old CRT-TV (Cathode ray tube)
Most widescreen TV are either LCD or Plasma screens. In some countries was also made available for analogue TV. It was then called PALPlus.
Most common ist 16:9 although some manufacturers chose their own formats. This is less than ideal if you thing about that most TV and cable stations broadcast in a standard format. This is either 4:3 or 16:9. If your television does not meet the standard the picture has to be stretched or cropped to make it fit. There will be massive black bars on either side or bits are cut off at the top. Both affect your viewing experience.
At the end it is therfore up to you as a consumer to chose wisely. If you watch mainly DVD and Blue Ray an ultra wide Philips is for you. TV watchers are probably better off with a regular 16:9 format.
Another thing that matters is size. Back with your old CRT-TV anything bigger than 22″ screen size would have been considered big. In fact CRTs were only available up to about 40″ and they were monsters that would weigh a ton.
With widescreen LED and Plasmas 40″ is more or less where it starts getting interesting. The sizes are simply a completly different story. For your living room a 32″ would be considered small if not tiny. A decent size for a small room is 37″. Even in a rather small room most people would start looking for a screen that is at least 42″.
I would say that these days 55″ is probably the most common size.