Steven: If your plan is to stay in this home for some time, I suggest that you run 3/4 pipe to each area of the house that has plumbing(both hot and cold) it will be much quieter, and last longer as well as provide a more equal flow of water to all your fixtures. Most new codes require the installation of Scald Guard type shower fixtures, these balance the pressure to prevent fluctuations in temperature of water to the shower and prevent unpeasent surprises. If the water piping is to be of copper, use Type L through out ( the difference in cost is well worth the benefit) and if copper pipe is to be used be sure to install a Copper Knight in the system to insure a lifetime of trouble free performance. If this is to be a two or more story structure, you may wish to insulate the vertcal portion of the sanitary drainage system to prevent embarassing noises in the walls when the toilets are flushed on the upper floors. Lots of luck with your building project. Bud Suncoast Plumbing Inc. Sunny Florida.