please, i used to gameon the laptops for 2 years, on dell inspiron XPS system, and i have this to say-
a true gamer really needs a desktop, at first on laptops everything will work fine, but later on if the frame rates drop or something goes wrong, there is no way to tell what happened because ytou cannot open up your laptop, you will eventually have to send it to the manufacturer, who will make you go go through a lot before replacing anything. Also very very expensive and hard to upgrade videocard if possible at all on notebooks.
on desktopss, you can replace individual parts, thats all i have to say! Nootebooks are cool and mobile, but in the long run gaming solution, not worth it. (
Now i own both, inspiron XPS and a dell 9150 dimension.