There is a strong positive correlation between how much a laptop weighs and what it can do. It is not a difficult concept; the more things a computer can do, the bigger it is and the more you have to carry around with you.

click to enlarge
Some notebook computers are capable of handling four or more spinning drives at one time (hard drive, DVD, floppy, and
external drives). Such capability comes with two prices, the actual dollar amount you must spend, and the physical weight associated with more equipment.
Some laptops are truly desktop replacements; they are capable of everything a desktop computer can do. If you need that kind of power in a portable computer, spend your money on the best laptop you can afford.
However, many laptop consumers do not think carefully about how they will be using their compact computer. Ask yourself: Do I really need the ability to burn double layer DVDs while I am on the road? Is that 17-inch screen really going to do something for me that a 15-inch screen would not? Will I really need a built-in video camera on my laptop or do I just think it would be neat to say I have one?
Think realistically about how you will be using your new laptop computer on a day-to-day basis. Many people find that 90% of what they do with a notebook computer are simple tasks such as word processing, using spreadsheets, or composing e-mail. These tasks do not require the latest and greatest technologies and certainly do not require many external and internal peripherals.