I'm not affiliated with the developer or product. In continuing to replenish my new MacBook Air, I was going through my old emails for registration codes of programs I purchased. One I received during a MacHeist was called Squeeze. It's been renamed to Clusters, and I've installed it on my MacBook Air. What it does is compress files and folders seamlessly in the background, and uncompressing them live as you use them. I compressed my entire Applications and Home folders and was able to recover 2.61GB of space. I've launched all my large applications that were compressed, and I honestly can't tell the difference in launch time. http://www.clustersapp.com/ If you're serious on retaining as much free space as possible, I would recommend trying out the software. For $13, it's very much worth it.