We have had no less than 7 waterline breaks between the meter and our townhome which is about an 85 foot run, the last 4 or 5 we have patched. The first 20 feet or so are up a large grade in a natural area with 3,30 foot tall trees and mature bushes and shrubs. With another leak I am going to replace the entire line, I am told that our neighborhood has pretty high pressure spikes. My question is, the plumber has suggested putting a pressure valve which a lot of our neighbors have done but also reducing the line from 1" to 3/4" to the house, does this sound correct? Will this be stronger or will it cut down on the amount of available water?

Reducing the pipe size will do absolutely NOTHING to reduce the pressure.What kind of pipe do you have? Is it blue?

The pipe has all been replace but in stages, we did the top part then replaced the lower section. The pipe that is in the ground is actually a black pipe, the plumber is recommending we use a product called Pex? And we are going to run a whole new line top to bottom about 85 feet worth and to handle the spiking pressure he suggests using a pressure valve on our side on the meter. Does this make sense?

yes.