Updated navigation and sorting. Lightroom 1.x may have suffered from trying too hard to replicate the standard professional photographer work flow which involves a light table and slides. As such, it neglected the realities of how files are stored on a computer and made navigation and collections difficult. Now, Lightroom's Folders section has clearly labeled hard drives so that photographers can work from not only multiple hard drives in a computer, but with increasingly common external hard drives as well.
Also new are Smart Collections. These collections are familiar to anyone with a digital mp3 player. They work by setting up parameters which, when met, cause a photograph to be included in the collection. For example, a Smart Collection could be defined to include all photographs taken before 2007. When photographs are added or changed, the contents of the collection automatically changes as well.
The new Filter Bar allows for quick and easy filtering on just about any possible data that exists with the image files. Everything from the file name to any metadata field, and of course any Lightroom set parameter such as flag colors.
One of the most frustrating things about keywords is accidental duplication or more precisely, the creation of new keywords when the one you want already exists. The difference between Mom's House and Mom House, for example. Now, as you work with your photographs, and in particular, as you assign them keywords, Lightroom suggests keywords that already exist.
In the Printing window, Lightroom now supports the ability to print contact sheets with more than one size of photograph, though it still can only be one photograph. Now, someone wanting to print a 5x7 a 4x6 and a couple smaller photos from a single sheet of 8x11 paper can do so if they can find a way to make them fit. Even better, such layouts can be printed to jpeg files so that they can be saved or taken to a printer.
Print Sharpening has been improved by eliminating the three choice model in favor of an algorithm that automatically determines the correct amount of print sharpening.
The slide show panel now supports a beginning and ending slide being added to the show so there is no need to "fake" one with a blank picture.