for Quality: MacIntosh or IBM/Lenovo Thinkpad.
Avoid, for reasons of early failure and poor parts availability: Sony VAIO, eMachines, Compaq, Acer, Alienware, WinBook, and any cheapo in the bottom third of the manufacturer's price list.
Cheap laptops are just cheap. Their cooling is usually badly designed, the LCD screens fail early.
If reliability means anything to you, do not buy a cheap laptop, as the screen failure is high. Get a model that is widely sold so you will have good parts availability in four or five years when parts begin to fail.
The most significant problems we see are in cooling, earlier failure of LCD screens, and failed optical drive burners. Also, high speed hard drives (7200 rpm and above) fail much earlier
Good laptops have enough room, and enough fans to move a lot of air in and out. They also offer access so you can periodically remove dust, pet hair, etc. You will find an offer long warranties. Parts available for seven years. Memory capacity exceeds 2 GB. They have removable video graphics cards.
We think the IBM Thinkpad far exceeds other brands and models, and that the additional cost is justified for both IBM and MacIntosh. Next, we like Dell Latitudes, and Inspirons, in the top half of the price range. Tied with Gateways. HP's in the upper half of their model range are very good. We would avoid all others. Toshiba makes a good laptop, but has extremely poor warranty repair and parts availability nowadays.
We do NOT recommend any laptops as gaming machines, unless you can afford to replace it every 18 months.
Look for lots of USB ports, Firewire ports, PCMCIA slot, serial ports, and other stuff that is "old fashioned" as that shows more effort has been put into the machine.
MacIntosh is simply the best where a lot of design work is done.
Get one which offers a choice of a long warranty.
Avoid Sony and the others mentioned above.