Laptops can and do work as gaming platforms.
I know because I've used one when I don't have access to my desktop at times. Being away from home or what have you, they come in very handy. For a long time, about a year, back in AH1, my laptop was all could use due to limited space at college.
Many laptops today have stang alone video cards. The higher end laptops such as Alienware and their Aera 51 laptop which I purchased has a 256 mb ati card. And plays Aces High very well.
The Laptop I had before the A51 was a Dell 8100. P3 1.3 ghz 512 Ram and I upgraded to a 64mb card. I did this myself. Its nothing short of a pain in the arse. Finding the right card for your machine and then installing it are both difficult at best. But it can be done. It runs AH2 but that's about it. You start getting around crowded areas or smokey fields and the system quickly falls on its face. The upgrade was cheap and basicly all it cost me was my time. And it was not for the sole purpose of being able to run AH2.
So to say that they cannt be upgraded and are not gaming systems is false.
If you have a choice get a desktop. Better yet do as I did and many others do and build your own.