Ok, time for me to show off my awesome laptop that'll blow all of your computers to pieces!
Acer Aspire 5720G Laptop
Intel Core 2 Duo T7100 @ 1.8GHz
ATi Mobility Radeon HD2300 w/256MB DDR2 (AKA The Powerhouse)
160GB Seagate 2.5" 5400RPM HDD
External WD 1TB 7200RPM HDD
Logitech Z-2300 and Z-4 2.1 Speakers
Microsoft Notebook Optical Mouse 3000 (which I use on my couch armrest to play!
....and of course the generic laptop keyboard!
So as you can see, with my awesome rig, I can easily get a nice, fluent 30FPS in COD4 on minimum and at 800x480 res, sometimes even 40FPS if I'm lucky