I was married 9 years ago and still have my custom made gown.  I'm a big history buff, and during the entire wedding planning and celebration, I was sure to save things that I would want to share with my children and grandchildren.  I saved things like our wedding planning book, bridal magazines, etc., because I knew that someday it would be fun (and funny) to check out the styles from 1999 (the turn of the century!).

Also, I'm planning on using the fabric from my detachable train to make my children's baptismal gowns (whenever I have children). 

My mom has her custom made gown, and even though my sister and I could never wear it because she was a size 0/2 (and short), we loved looking at it. 

Even though you don't have daughters, maybe your future daughters-in-law may want to use some of the lace on their own gowns, or to wrap the stems of their bouquet.  It would be a nice way to incorporate something "old" into their wedding.