Their are many many benefits to keeping your original wood windows. Your wood windows most likely were hand crafted from cedar or fir. It is not easy to find high quality wood windows, especially hardwood windows, being produced today and if so they are quite expensive. This means that your home will hold more value with the original windows. This dense wood does not succumb to dry rot easily.
Wood windows are the most revered windows on the market.
Your wood windows were built for your house and therefor match the design and and aesthetics.