Although not as "numerically precise" as a real torque wrench, general-purpose hand-held power drills (which you can use as a powered screw driver, of course) usually have a torque-sensitive limited-slip clutch (don't know the correct term!), which will prevent you from over-tightening wood screws. I have a battery-powered DeWalt, which is very nifty as a screwdriver, too.