Walls and Ceilings - replace or repair??

I recently purchased an older home, and most of the walls are plaster and lath. I was wondering if I should go through the trouble of removing it and putting up drywall, or leave it up and fix the bad spots???? The walls and ceiling are in pretty good shape. I also need to run some wiring, and replace the windows. I have spoken with several people and they all have a different opinion. How will this effect the value of the house? Is drywall really that much better? The rooms aren't that big, but if their isn't a need to replace the plaster---should I??

I would leave plaster up, if possible, in an older home.
You can repair cracks in plaster with 6"-8" wide strips of black plastic screen wire applied just like you would do seams on drywall. Mud it in with sheetrock mud, sand and paint.
The black vinyl screen wire will stretch and not crack like a repair that just had mud over the crack.
Replace the windows and re-wire first, of course.
Experienced pro electricians can re-wire homes with plaster with minimal damage, but there will be some wall and ceiling damage. They hopefully should be able to feed new wire from above and below in walls, but will have to make a path for ceiling wiring.
Keeping the plaster in an older home will maintain and enhance the value.
Good luck!