Grab this Update if you have been experiencing any problems with your macbook/Macbook pro keyboard, as it will most likely eliminate the problem. Details listed below
"This MacBook and MacBook Pro firmware update addresses an issue where the first key press may be ignored if the computer has been sitting idle. It also addresses some other issues. The update package will install an updater application into the Applications/Utilities folder and will launch it automatically. Please follow the instructions in the updater application to complete the update process."