We just bought an old house for rental income and are in the process of remodeling. One major improvement to the house was the addition of all new windows. The house was built in the 1940's and the windows we removed were original to the house.
Here are some ideas I've found for re-purposing old windows. I just did a Google Search of "Antique windows as art" and these photos popped up.
If you have any other suggestions on ways to use the windows, please share!