Variable. What is your system specification and which games do you plan to play? Your screen resolution is very important too.
I'm thinking of buying a notebook probaby the new DELL INSPIRON R series so it will have core i5-2510M and around 4GB of RAM. There's and option between INTEL HD GRAPHICS 3000 or AMD RADEON HD 6470M. Upgrading to the Radeon will cost $75 more. So will it be worth a upgrade from the HD graphics.(I'm not a serious gamer and i'll just run games like Warcraft, FIFA 11 etc. 1024-768 resolution would be a ok for me).