We've noticed that a lot of humanoid robot builders will spend a thousand dollars or more for a great robot kit and then end up damaging the screw heads as they work through the assembly process. Since the typical robot kit has literally hundreds of screws, and all of them are tiny, using the right tools can mean the difference between a really positive happy experience, or hours of frustration and sore wrists.
Although it isn't obvious to most people, it turns out that there is a big difference in screwdrivers, especially in the amount of metal to metal surface contact they apply to the screw. "Tatwood" on the Robot Magazine forum drew on his years of experience building RC model cars and planes to put together a very useful tutorial post on selecting the proper type of screwdriver. It's definitely worth checking out.
A couple of additional comments: As the tutorial mentions, you should certainly consider purchasing a good (not the cheapest) power driver. If you do use a power driver, always make sure that you do the first few turns by hand to get the screws started, and the last few by hand as well. Don't depend on the driver's built-in clutch to insure that the screw is properly seated. Also, for some reason lost in history, the Japanese refer to the two types of screw heads as 'plus' and 'minus', not Phillips. If you happen to know the background on this, please let us know.