I have a journal - I started with a binder. For each quilt, I have samples of the fabric, and usually a sample of one of the blocks (usually one of my practice blocks), who it was for, a photo of the quilt, and another photo of the quilt with their new owner. I usually have a 'story of your quilt' to go along with the gift, and have a copy of that in the binder too.
The 'story of your quilt' is a collection of my thoughts for the recipient - why I made it, the pattern, why I chose it for them, what the pattern means to me. For example, one of my first quilts was a 'Sunshine & Shadows' quilt for a wedding gift - for me this symbolizes perfectly what the young couple will experience - sunshine & shadows, ups & downs, good times & bad, and together it makes a wonderful experience.