You are getting so many suggestions here. Personally, I would do something quick and simple in the neutral colors and throw size. Even if you look at her wedding colors or those of her home, that will change over the years. Too, you don't know how well she will treat the piece so I wouldn't invest a lot of time. A rail fence can be quite interesting--not really modern nor traditional and works up quickly. What colors do you have in your stash that you'd like to use up but would be pleasing to anyone's taste? I recently did a chevron (half square triangles) that went quickly but chevrons are a bit on the trendy side that may not look as good in another 5 years. Rail fence is an "oldie but goodie".