Advantages

Laptop computers are portable and can be used in many locations. Shown here is former Mexican president Vicente Fox.
Portability is usually the first feature mentioned in any comparison of laptops versus desktop PCs.Portability means that a laptop can be used in many places—not only at home and at the office, but also during commuting and flights, in coffee shops, in lecture halls and libraries, at clients' location or at a meeting room, etc. The portability feature offers several distinct advantages:
Getting more done – Using a laptop in places where a desktop PC can't be used, and at times that would otherwise be wasted. For example, an office worker managing his e-mails during an hour-long commute by train, or a student doing her homework at the university coffee shop during a break between lectures.
Immediacy – Carrying a laptop means having instant access to various information, personal and work files. Immediacy allows better collaboration between coworkers or students, as a laptop can be flipped open to present a problem or a solution anytime, anywhere.
Up-to-date information – If a person has more than one desktop PC, a problem of synchronization arises: changes made on one computer are not automatically propagated to the others. There are ways to resolve this problem, including physical transfer of updated files (using a USB stick or CDs) or using synchronization software over the Internet. However, using a single laptop at both locations avoids the problem entirely, as the files exist in a single location and are always up-to-date.
Connectivity – A proliferation of Wi-Fi wireless networks and cellular broadband data services (HSDPA, EVDO and others) combined with a near-ubiquitous support by laptops means that a laptop can have easy Internet and local network connectivity while remaining mobile. Wi-Fi networks and laptop programs are especially widespread at university campuses.
Other advantages of laptops include:
Size – Laptops are smaller than standard PCs. This is beneficial when space is at a premium, for example in small apartments and student dorms. When not in use, a laptop can be closed and put away.
Ease of Access - Most laptops have doors on the underside that allow the user to access the memory, hard drive and other components, by simply fliping the laptop to access the doors. For desktops the user must usually access the backside of the computer, which is harder if it's in an area with little space.
Low power consumption – Laptops are several times more power-efficient than desktops. A typical laptop uses 20-90 W, compared to 100-800 W for desktops. This could be particularly beneficial for businesses (which run hundreds of personal computers, multiplying the potential savings) and homes where there is a computer running 24/7 (such as a home media server, print server, etc.)
Quiet – Laptops are often quieter than desktops, due both to the components (quieter, slower 2.5-inch hard drives) and to less heat production leading to use of fewer and slower cooling fans.
Battery – a charged laptop can run several hours in case of a power outage and is not affected by short power interruptions and brownouts. A desktop PC needs a UPS to handle short interruptions, brownouts and spikes; achieving on-battery time of more than 20–30 minutes for a desktop PC requires a large and expensive UPS.
All-in-One - designed to be portable, laptops have everything integrated in to the chassis. For desktops (excluding all-in-ones) this is divided into the desktop, keyboard, mouse, display, and optional peripherals such as speakers, and a webcam. This leads to lots of wiring. It can also lead to massive power consumption.