The thing is all plain macbooks still use built in intel integrated graphics and cpu speeds are so quick that unless you do seriously cpu intensive stuff (e.g. compression, calculation, etc) you won't be able to make use of the cpu power.
Thats why if i ever get another macbook I will make sure its a macbook pro. But most likely I will end up just buying a new desktop to play games with and save the cash for a seriously good pair of speakers and a hhkb pro 2.
Seeing as my macbook hasn't died after a couple years I am satisfied I didn't invest in applecare, i'm probably more safer with it since it rarely leave my house and the keyboard and monitor and track pads are all being left unused with my external peripherals, I did upgrade it with a 320Gb hard and 2Gb of ram though. So it has been slightly modified, my main gripe with macbook is only 2 usb ports and no esata port, and also I bought the basic macbook so no dvd-writer