No, but most are. For starters, here's a thing or two you should know about TV resolution: The television images you've come to know and love are called standard definition (SD). They are made up of 300,000 pixels in a 640-by-480 configuration.
Some smaller LCDs (less than 30 inches) still use this arrangement and are therefore not high-definition sets. High-definition TVs must have a screen with a lot more pixels - nearly 1 million in a 1,280- by-720 configuration (which is called 720p).
But it doesn't stop there: Newer, more expensive models have around 2 million pixels, double the resolution of 720p (they're called 1080p TVs). Although eventually all TVs will be 1080p, only people with the latest video-game machines (a few people) and high-definition movie players (almost no one) will get the most out of them now, and it's going to take a while.
You can still enjoy incredible clarity viewing television shows and DVDs with 720p.