I haven't been sure how high my saddle should be, either. Inspired by this post, I took a look around and found this site.

http://www.bikeradar.com/fitness/art...t-right-14608/

I just ordered a goniometer from Amazon for $12.

With the current saddle height, I can reach the ground on both toes while sitting on the saddle. I wonder how different the saddle position will be based on the goniometer method.