Leopard Hack: Make Leopard's menu bar opaque.
For our first Mac OS X 10.5 Leopard tips, we've been collecting a variety of popular visual tweaks and most-requested adjustments to Apple's updated interface. Because our readership includes a mix o fusers, we've presented each hack in a technical and non-technical format.
If you've recently upgraded to Mac OS X Leopard, and find yourself disliking the new translucent menu bar, here is the hack to make it opaque again.
Less Technical: Use MacParc's Leopaque utility.
For less technical readers, the easiest way to get your old opaque menu bar back is to download MacParc's handy Leopaque utility.
Adjust the slider from a setting of grey (0) to white (1) and click "Enable." Choosing a setting of 0.62 gets you the closest to the menu you are used to in the previous version of Mac OS X. This hack does require that you enter your administrative password and restart your Macintosh.
Using Terminal: Make Leopard's menu bar opaque
For more technically inclined users, here are the terminal commands to apply this hack. Please consider yourself sufficiently warned that using terminal, and especially the sudo command can break your computer if mishandled.
Make menu bar opaque:
sudo defaults write /System/Library/LaunchDaemons/com.apple.WindowServer 'EnvironmentVariables' -dict 'CI_NO_BACKGROUND_IMAGE' 0.62
Make menu bar translucent again:
sudo defaults delete /System/Library/LaunchDaemons/com.apple.WindowServer 'EnvironmentVariables'
Source: This hack first appeared at the great Mac OS X Hints site. MacParc's Leopaque utility is based on this same hint. John Gruber's excellent Daring Fireball gets credit for identifying 0.62 as the best value to mimic the old Apple menu bar.