Little background....I was an engineer in the military for close to 20yrs, and an electrician/mechanic before that, so I have a bit of experience here. Yes, EMF is a real health concern, but No, it is not a concern from normal everyday household/business environments. Anytime current is sent through a wire, AC (what you plug in) or DC (battery power), it creates a magnetic field around that particular wire. The more/larger the wire coupled with high currents equals bigger EMFs. Power tools don't give off much of an EMF. The power going into them induces a motor with brushes which knock down the field to next to nothing. Computers put out a surprisingly small amount of EMF. Everything has to be shielded, otherwise the fields would wipe out the hard drives and ruin other delicate parts. You get more harm from fluorescent lights than from your computers (fluorescents are a different topic).
Where EMF becomes a health problem is housing units built under high voltage transmission wires. The huge x-country lines put out so much EMF, it's possible to park under them and get a reading on a meter out of the air. A guy was actually arrested a number of years ago for winding a bunch of welding cable around a big piece of copper and putting it under some transmission lines. He used the power generated to run his chicken coup. He was essentially stealing power.
There are a number of studies linking cancer and birth defects to living under these transmission lines. But in normal everday activities, EMF isn't a concern.
Hope I cleared some stuff up.