After weeks of guilt over the fact that I'm not getting out to walk enough, I've finally found the solution: a good walking buddy who will get up early with me every morning and hold me accountable. She never says she forgot, and she doesn't whine about wanting to sleep five minutes longer. She doesn't scream and cry about how she'd rather play in the backyard.
The only downside is that she poops in the neighbors' yards and I have to pick it up with an inside-out plastic bag. Oh well--no one's perfect! And at least this ensures we won't have a dog poop minefield in the backyard. She looks like she could really mess a bad guy up with those crooked teeth sticking out. And I bet she would, too.