Larger than either the ultra portable or the thin-and-light, the mainstream laptop offers the features of a desk computer, but still gives a bit of portability. They have a 15-inch screen - or bigger, big keyboards and with their standard selection of ports are almost as good as your everyday PC. They weigh in at 3-5 kgs, so you wouldn't want to lug them about for the whole day.
The desktop replacement is the laptop for - well, replacing your desktop PC! At 6 kgs you certainly wouldn't want to lug it around the streets. But it has all the power of a regular PC and can support an extensive range of performance parts.
The screen size goes up to 17 inches, but the battery life is poor at 3 hours. However, you can usually plug them in to a power point somewhere.
Widescreen laptops are a marvel, allowing you to easily access and view two documents side-by-side. Of course, they are also great for viewing DVDs. Many laptop commercials show people using them at the beach; in reality, the screens are not usually of the type that allows for easy outdoor viewing. Transmissive - lit from behind - screens are almost invisible outside; reflective LCD screens are better for outdoors, but inside they seem dim.
