Very fun tip here. Once you do this, when you hit the spacebar to use Quicklook to make the folder show and cycle through contents of the folder. Some say it also reports for zip archives. 1. Open Terminal 2. Paste the below and hit enter defaults write com.apple.finder QLEnableXRayFolders 1 3. Relaunch Finder via > Force Quit... > Finder, then click Relaunch Via: http://www.macosxhints.com/article.php?story=20090912030240376
Nice tip. You can also click on the finder icon by pressing control+option key at the same time to Relaunch.
That looks pretty sweet, but not that useful. Galing how the files change thou. If you want to view the full content list of folders and zip files when QuickLooking them (is there such a word?), install the two plugins found in this site. That one looks less sweet than this xray folders view but its more useful. 10.5 only though, not compatible yet with Snow Leopard.
SL compatible, for those interested. I actually prefer using Quicklook plugins just like what zz pointed out. Makes for checking out downloaded files much quicker, like for PSD and FLV files and even IPA files (iPhone Apps). Yet more Quick Look fun here: http://www.qlplugins.com/ and here: http://www.quicklookplugins.com/