TinkerTool for Mac OS X Lion is a Must Have for Customizing 10.7
TinkerTool is broken into 12 main sections covering Finder, Dock, General, Desktop, Applications, Fonts, Font Smoothing, Login Items, Safari, iTunes, QuickTime X, and Resume (OS X Lion’s Restore feature), each section has a handful of options ranging from UI tweaks to behavioral changes. The other great thing is that you can always return to the default state and undo all the changes you make, meaning there’s no threat of accidentally screwing something up.
A free download, the new version is updated with a ton of OS X Lion specific tweaks and customizations, adding to it’s already robust abilities. It covers tons of things we’ve discussed here in the past, and everything is enabled through the apps simple GUI by just clicking on checkboxes. No defaults write commands, no digging around in /System/Library/CoreServices/, it’s by far the easiest way to access many of the hidden features of Mac OS X.
If there’s only one app you get for customizing OS X, TinkerTool should be it.