After adding support for OS X 10.9 Mavericks in its version 5.0 release, TinkerTool 5.1 from Marcel Bresink is now sandboxed for better security. The under-the-hood customization system utility also does away with the Login Items pane as it’s no longer useful for Mavericks, differentiates between the actual Lucida Grande typeface and the new screen system font introduced with OS X Mavericks, reinstates the preference setting that enables you to copy text displayed by Quick Look (for 10.9.1 and later), and reduces storage space used by the preference reset feature. While the latest version of TinkerTool requires 10.9 Mavericks, Bresink continues to offer older versions of TinkerTool for those running previous big cats, all the way back to 10.1 Puma. (Free, 3.9 MB, release notes)
Disable Caps Lock
If you find yourself pressing the Caps Lock key accidentally as much as I do, note that you can disable it entirely in Mac OS X. Open the Keyboard & Mouse preference pane, click the Modifier Keys button, and in the dialog that appears, select No Action from the Caps Lock pop-up menu. You could remap it to another modifier instead, but that might make using differently configured Macs more difficult.