If the windows aren't right, the house won't be right. Every dollar you save on the vinyl windows will reduce your market value by at least the same amount, likely more. Curb appeal is a very large factor in price and the wrong windows will really stand out in an otherwise sympathetic addition

Definitely need to stay with wood windows, to maintain cohesive appearance. Have you considered the vinyl windows that look like wood? Only a few manufacturers make them. They are more expensive than plain white windows, but more affordable than custom wood windows.

We have a 1925 bungalow that needs all new windows. I love the Marvin Next Generation windows - they're just beautiful - but they're out of budget. We went with Marvin Integrity wood / ultrex. Wood inside, the clad outside, and they're absolutely good enough. Grills are available to tie them in with the rest of the house, if you want them. It's a great window, and the removable panes make washing them a breeze.