Whether you are looking for a lightweight device to handle low-demand Web browsing and document writing or a Death Star-size desktop replacement, the perfect notebook for you is out there somewhere. But try to get what you want at the outset: Laptops are trickier than desktop PCs to upgrade.
Battery life: Notebook battery life continues to improve--especially in the ultraportable category--but the times that vendors quote tend to be inflated by being measured under optimum conditions, with the power-draining wireless receivers turned off and often with the extended-life battery (which usually costs extra). In PC World Test Center tests, laptops equipped with a T7200 Core 2 Duo processor had battery lives ranging from a little under 2 hours to as long as 5. The results depend on which of a multitude of components are sucking power under the hood. Check the fine print to learn whether the notebook was tested with the standard battery.
CPU: Vendors slap an Intel (or AMD) logo on a laptop, cite a speed, and leave it at that. Rarely do they acknowledge that laptops with low-end CPUs can barely get out of first gear running Vista. Beware of processors that run at less than 2 GHz. Intel Centrino 2-powered laptops have roared through our WorldBench 6 performance tests. But don't expect Centrino performance out of Intel's Atom processor, a hamster-wheel CPU designed to run sub-$500 mini-notebooks.
GPU: Most laptops rely on basic integrated graphics chips. That's not an ideal component for playing recent 3D games (including social network games like Second Life) or running high-end graphics programs. To handle those capabilities, look for a laptop with a discrete nVidia or ATI graphics chip. But the extra graphics power comes with a catch: Laptops with discrete chips tend to be larger and heavier, as evidenced by some of the mammoth gaming notebooks on the market.
RAM: Even though a laptop's RAM is relatively easy to upgrade, you should still buy as much memory as you can at the outset. Most laptops have two RAM slots, and it's not uncommon for a machine configured with 2GB of memory to have a 1GB module in each available slot. But if you start with this configuration, upgrading to 4GB of RAM later on means paying for two completely new RAM sticks. By opting for a generous quantity of RAM from the get-go, you won't need to spend money down the line on upgrading your sticks.
Weight: Ads often omit "little" things from the laptop's declared weight--like the battery and power supply, which you'll likely carry with you when you go mobile. Before you buy, ask what the total weight of the product is with these critical accessories included. Better yet, go into a store and do a few power-lifting reps with the machine in its road configuration.
Screen: Though it certainly is important, screen size tells you nothing about how well you will be able to read text. Ask about the laptop's native resolution--and see it for yourself. And while you're at it, test the screen coating, too. The very thing that makes images pop on the show floor can make it unusable in broad daylight. Some laptop screens bounce reflections like a mirror, which can make them very difficult to use outdoors. LED-backlit screens provide greater brightness, though they do jack up the price.