The majority of people would be "technically" unaffected. The obviously weird situation would be the main concern but in general most people wouldn't be in any life threatening situations. Think massive hurricane and how they affect the area (more on this later.)
All vehicles would stop, this wouldn't cause that many automotive accidents as they'd just slowly come to a stop. Breaks and steering are mechanical so that would still work.
Boats would stop, but that wouldn't affect much except being at the mercy of currents. Bigger boats could have bigger issues if near ports or other objects are their momentum would carry them on for a bit.
Airplanes are tricky. Some planes (even large passenger planes) can glide mechanically, others can't.
Power stations are interesting. Most have multiple fail-safes. Nuclear included. for example, many nuclear plants have the control rods held out WITH power, so when they lose power the control rods drop and reaction stops. It isn't all that likely that any of these would fail catastrophically, they might fail, but not with a bang.
So where are the real problems?
Medical care. Any patient being kept alive with the help of an electric device. Pacemakers, insulin pumps, air pumps, IV feeds, and so on. Granted many of these are in care settings like hospitals and health-care buildings, but there aren't enough health-care providers to deal with all of these.
Certain other utilities could suffer decent problem, but likely not life threatening or catastrophic. Say sewage or drain pumps, there might be a decent bit of flooding in some tunnels.
Another concern would be the lack of communication. This could cause problems such as panic, rioting and looting, or it could change nothing. Location and societal differences would change the outcome here. Keep in mind this is still just one day. The lack of communication makes organization very difficult. The government can't do much to help, people don't know what to do or where to go. Some go home, some go wild. It would take time for people to go crazy without knowing if this is the new way of the world or not, and how far reaching the effect is.
At the end of the day it would be a freak occurrence everyone would remember and loss of life would likely be high, but it wouldn't be nearly as catastrophic as you'd imagine.
Bringing up the hurricane from the beginning. There is a bit of everything when a hurricane comes through and wrecks the infrastructure of a place. In general people try to keep their lives intact. Power and utilities fail. Communication becomes difficult or impossible (except radio). Looting does occur, some people do commit crimes. The first day is rarely the worst, however.
OH! Also fringe case. Everyone dies. Electricity with the brain and heart stop too, so all life stops.