I have wanted to revamp my bedding for some time now. Here are a few covers I found that I like:
Here, here and here (this last link is my favorite!).
However, bedding is expensive! I was inspired to make my own duvet cover out of two flat sheets by this tutorial.
If I found some flat sheets on sale I could make a beautiful duvet cover, embellished with ruffles, for significantly less money than buying one.