One of my favorite applications that I use all the time is Adobe Lightroom. After trying out almost every popular photo-managment software including iPhoto, Picasa and Aperture, it was pretty obvious that Lightroom was the robust choice to handle my 60GB+ worth of photos. One of the coolest features I like about Lightroom is that you can buy and download Lightroom presets. These presets can be programmed to do anything from converting a photo to black-and-white, removing grain and dust or just enhancing and sharpening dull or darkened photos, all with a single click. You can find a few presets on The Bell Sisters website.
The one preset that I love the most and probably use on almost all my photos is “Punch”. Its a default preset that comes with Lightroom and can be found towards the bottom of the Lightroom presets list. Punch basically takes any photo you give it, and bumps the “Clarity” level on the photo by 50 points and the “Vibrance” level by 25 points. This removes some of the dullness or gray-ness of the photo that you might have inherited especially if you have shots taken in a cloudy environment and makes it, in my opinion, the easiest way to cleanup a photo.