There was a lot of damage to a plaster wall in our house. The botton 4' of the wall is now bare (down to the slats that the original plaster was put on). Any suggestions on how to repair with dry wall and there not being a huge noticeable seam between the two?

Ok you are hoping that someone has a trick to make several thicknesses of drywall come out exactly the thickness of you plaster wall. Sorry, not going to happen but you can get close. Take a measurement of the plaster thickness from surface to face of the slat. Drywall comes in many thicknesses but I doubt that one sheet is going to do it but a combination of two sheets should get you close. 3/8, 1/2, 5/8, 3/4" any combo of these sheets get close to your thickness? Back to you

If you can't find 1/4" or 3/8" drywall you can always use plywood. 1/4" luan is only 3/16" thick. With some combination of these materials you should be able to come out to with in 1/16" of the plaster. Close enough for drywall with a little finishing work.