Do half of your pictures look like they were taken from a slanted surface due to you always holding the camera slightly askew? Not mine. But hey, if that's a problem you run into, this camera cube level will solve it for you in no time.
Simply snap the cube on top of your camera on the flash mount and you'll always know exactly when it's perfectly level. It's great for holding the camera in your hands, but is probably even more useful when you're using a finicky tripod. This way you'll know for sure when you've got the legs out at the proper lengths. It's available now for $15.