people selling "raw" LCDs at a fraction of the price, sadly these are of no use on the arduino
I basically agree, but just to clarify this: The DOG series of graphics LCDs has an internal RAM and also an internal controller. Pixels keep there value until a new pixel value is written. But indeed the display memory is an issue. The Arduino Library for the DOG displays uses a small trick and only requires a fraction of that memory. For example for the DOGXL160 display, only 160 bytes are required (DOUBLE_MEM disabled). So there will be enough memory for the application itself.
Perhaps I should also mention, that I am not in any way related to EA. I just find these DOG displays very nice.
Finally I personally would prefer to use one of the smaller DOG displays, which are much cheaper than the DOGXL160.
Oliver