My small (1,100 sq. ft.) 1950's house was completely rewired about four years ago at a cost of $4500 for a 200 amp service, a new meter and mast outside, all new wiring and addition of about 10 or 12 new outlets. I HAD to do this first because of safety issues. The P.O.'s (previous owners) had put 30 amp fuses into a box designed for 15 amp fuses, heating up the box and wires. This heat causes the insulation on the wires to dry out, crack and fall off, leaving exposed bare wire inside the walls. If you have a fuse box, check to make sure that the fuses are the correct size.
The cost was a little overwhelming but it is nothing compared to risking the chance of a fire in an old house. The pluses are peace of mind, a lot more outlets, outdoor outlets for plugging in electric tools outdoors and a wired-in smoke detector. My electrician did not have to cut a single hole in the plaster except for new outlets and the new box. It was a tough job and took about a week, but it was well worth it.
Get at least three estimates before you proceed and don't pay in full until the job is done to your satisfaction. Good luck! firstname.lastname@example.org