aLaunch
Application launcher operated from the menu bar features your choice of icon size, the ability to open files and folders, and categories that can be grouped between separators. Supports hot keys and folder hierarchies.
Caffeine
Set your Mac to stay awake when it’s inconvenient to have it fall asleep, for example if you’re watching a movie.
iStat Menus
Keep tabs on what’s going on under the hood with stats in the menu bar for CPU, memory, disks, monitor, temperature, fans and power, and Bluetooth. Plus, customize the date and time to your heart’s content.
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Also try: MenuMeters
MenuMeters
Keep track of what’s going on in your Mac with MenuMeters — a set of of monitors for CPU system load, disk activity, memory and network throughput. The cool thing is that they all sit on your menu bar.
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&mdash 1 so far
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MultiXFinder
Switch applications from the menubar much like they did in the OS 9 days. Lets you see background processes and assign shortcuts to the first nine entries in the menu. Several other options, settings and rules available.
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Also try: aLunch
Semulov
List all mounted volumes in your menubar, categorized by type. Clicking on a volume menu will unmount/eject that volume. Supports Growl unmount and mount notifications.
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&mdash 3 so far
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Xmenu
Add one or more menus to the menu bar for accessing files and data. Pre-set menus include Applications, Developer, Home, Documents and Snippets. Or define your own. (Not a system hack.)