Starting with iTunes 7, the popular digital media app began separating content into different categories based on type—Music, Movies, TV Shows, Podcasts, Audiobooks, etc. It's a nice feature, but what if you liked the consolidated view better? Macworld suggests a simple solution: Create an all-inclusive Smart Playlist. For example: The method I use is to create a new smart playlist (Command-Option-N) and then set the condition to Size - is greater than - 0MB, and check the Live Updating box. That's it; you've now got a smart playlist that will show you everything in iTunes, and update each time you add new content.
The author is quick to point out that while this method does the trick (on both Windows and Mac, mind you), it isn't quite the same as the old consolidated library, namely because a smart playlist is still buried in your playlists rather than sitting atop your sidebar. If you're on a Mac, the post describes how you can go one step further by making a couple of Terminal tweaks that will add the consolidated library back to the top of your Library. Of course, if you've been using previously mentioned Secrets—the preference pane that unlocks Leopard's hidden features—you can apply this tweak from the iTunes section of the handy app with the tick of a checkbox.
Add a consolidated library view to iTunes