Having bought a laptop last year I would now only look at 3 factors (price and spec' apart that is!):- Weight, Battery endurance, and quality of keyboard. Add display if you like, but I don't thinks there's a lot of difference these days.
Mine is heavier than I'd like, therefore it doesn't get half the use it could do. The battery will only last about an hour and a bit (despite what it's supposed to do - I find this a bit akin to printer speeds and how long ink cartridges should last!) and are heavy - therefore if I'm out on the train for the day (an ideal environment for laptop use) there's a risk that I will have a dead breezeblock weight to carry round for half the time. Consequently I tend not to take it with me!
For home use - well I don't use it as the desktop is so much better and easier. Desktops are cheaper and easier to upgrade too!