I also have a 3-ring binder - each quilt has a photo and samples from the fabric, and sample square (if there was a test one or left-over). Who the quilt went to, photo of the label, and I also try to get a photo of the quilt in its new home with its new owner.
I often do a 'quilt story' when I'm gifting - why I chose this pattern for this person, what it means to me. For example, I did a 'sunshine & shadows' for a wedding gift, as for me it symbolized all the good days and tough days to come - to know that you can't appreciate the good days without those rough patches :)
The pattern source is detailed (where I got it, who designed it, where I deviated from pattern, etc). If I did a mock-up in EQ, a print out of that too.
Thank you cards go in here too!