I read somewhere that there are two types of travel companions, and one is the kind who makes you want to bury a hatchet in his or her head halfway through the trip, and then there's the other kind. I've known both. Thankfully, much more of the other kind. Thankfully, loved ones have so far always been in the other kind camp. It's so disagreeable to contemplate burying a hatchet in the head of a loved one.

More often, though, I'm on my own. As another poster said, a camera is a good companion. And I write a lot in my journal when I'm travelling alone. I always think I will write lots of letters and postcards, and schlepp with me all the supplies for doing so, but in fact I never do get around to writing much to others. (If anyone knows a cure for that particular brand of laziness, please let me know.)