I keep a Christmas Scrapbook that I store with the Christmas stuff and only bring out once a year. It's not much now, but I'm hoping that in 30 years it will be really fun to look back on! Contrary to popular belief, I don't do much actual scrapbooking, but 2 pages a year is easy to maintain!
Each year I include:
1. Our Christmas card
2. A hand-written summary of how we celebrated Christmas
3. A few key photos of major activities, events or gifts
Here's a scrapbook page that I made recently. The butterflies are folded in half, but only adhered on one side so their wings are 3D. It's hard to tell, but I sewed on the middle of some, so the string ends look like antennas.