For last-minute gifts, don't forget the grocery store. Fancy olives, nuts, cherries, cheeses, coffees, teas, cookies, and even dessert mixes can make excellent gifts.
If anyone on your gift list is having a "first", like first Christmas in a new house or area, baby's first Christmas, or newlyweds first Christmas together, consider giving a Christmas journal or scrapbook. Everyone can contribute something, and it can be put away for next year, to start a family tradition.
Play detective -- notice which gifts, colors, fabrics, styles, etc. are the biggest hits. Notice what people GIVE -- it's a good clue to what they like. Notice the color schemes and decorating tastes of the homes you visit, for ideas for hostess gifts for next year. Check out other people's decorating ideas, to vary and adapt for your house next year. Take pics for next year's Christmas cards, scrapbook, and gift boxes/bags.
Take inventory of tree-trimming and gift wrap items. Now's the time to buy. When shopping after-holiday sales, don't forget the fabric and craft stores. You can ususally pick up holiday fabrics and notions half-price for next year's holiday tablecloth or throw-pillow covers.
a partial checklist:
Collect the good boxes to reuse next year.
Collect Christmas cards to recycle.
Candy boxes are usually very sturdy and well-shaped. Save them to cover with fabric or wallpaper for next year's gifts or decorations (centerpiece, potpourri, etc.)
When putting away your Christmas things, set aside anything that's broken or shabby. During the year, when the Christmas spirit hits, dig those out and repair or combine them into new decorations. Put your Christmas cards in the same place, for the same reason.
Often kids (or even adults) get "toys" that are either too nice to play with, geared for the wrong age, duplicates, Christmas oriented, or just too many. If you pick a few of these to put away for next year, you'll probably forget all about them and have a great surprise when you get out the decorations next year. This works really well for younger children, who sometimes get cranky waiting for Santa. They'll have before-Christmas toys, from last year, to help them get through all the hype, and it won't cost you anything.
The first time we did this was when our kids were small and a relative (who didn't have kids) gave ours something way too old for them. That same year, I found some really cute Christmas toys on sale. I put them all away with the Christmas gear and forgot about them. The next year, the kids were so thrilled with their Before Christmas presents that they came to me after Christmas and offered up some of their loot for their next year's surprise. That started a tradition we carried on until they were grown and left home. This tip has two added benefits. It helps get you into the spirit when you bring them out and it helps cover up for those occasional meager Christmases when the finances just don't measure up to the expectations.