Update plumbing?

[Kent Verge]

While opening up the walls in the kitchen in our recent purchase -- a home built in the 40's with galvanized pipes -- I uncovered a leak in the wall behind the tub in the master bath. I already need plumbing work in the second bathroom (a complete remodel), in the kitchen (moving the sink and dishwasher), in the laundry room (total new plumbing), and now the leak in the master bath. Should I just bite the bullet and update everything on the supply side? The water pressure is terrible and I suspect that the pipes are part of the problem.