I don't usually recommend products or services here, but this is cool enough to make an exception. It's a company called ScrapWalls that makes custom collages of your photos. A 20" by 30" poster is only $29.99 (plus $5.99 shipping), and smaller sizes are less. They offer a variety of shapes, but naturally I chose a U.S. map for a collage of my cross-country bike trip:
Click on "Pop Out" to view the above as a separate window.
Even better, ScrapWalls sometimes offers Groupon-like deals (in the past through Eversave and BuyWithMe, and currently -- for the next week -- through kgbdeals) for half-price. This could make a great Christmas gift, and it's an easy and inexpensive great way to get a bunch of photos up on the wall instead of buried on a hard drive. With a sale and a coupon, I got a sturdy frame at Michael's for only $12. Now if I can just find a place to hang it...
Note: With the irregular U.S. shape, some of the photos got chopped off. From what I can tell, most of the photos that are less than 50% visible are duplicated elsewhere in the collage, except for the pictures on the west coast (should be less of an issue with a simpler shape). The web site lets you rearrange the photos, but it may take some trial and error to get it just the way you want it. Or maybe I'm just too damn picky. The hardest part was deciding which photos to leave out, which is why I had to get the largest size!