I finally found a weather app that isn't just more of the same. MoWeather (free) for iOS is a graphically compelling weather app with all the usual stuff you want to see, along with a 15-day forecast. The weather background is nicely animated, like the Apple weather app, and it does my favorite Yahoo Weather app one better -- rather than finding a canned photo that reflects my location and weather, MoWeather provides a page of user-submitted photos that show the current weather at your location.
You can snap pictures and submit them all within the app. MoWeather also has a very nice idea built in -- with a click, you can email or text a map of your location and the current conditions to a friend.
The app also supports gestures. You can swipe vertically to update the current conditions, or swipe left to see your locations list.