Should I buy a drill or an electric screwdriver?
The screwdrivers are designed to work at a much lower RPM which makes them much more controllable.  They also have a lot more torque than the drill.  I've used both and the difference is night and day.  With the high torque of the screwdriver I have often driven screws into wood without predrilling at all.

Also the good screwdrivers have torque limiters that let you set the maximum torque--set the cutoff where you want it and when the screw is fully driven the limiter kicks in rather than snapping the head off the screw.