Here's one list:
Wired Magazine: The Smarter Emergency Kit
We always have water, flashlights (and batteries), candles, cash, and canned food on hand, as well as a radio that can be operated by a hand crank in case you run out of batteries. We're woefully deficient in the tool department, since my husband and I are about the un-handiest people on the planet. Even if we had them, we wouldn't know what to do with them!