We just counted 18 individual app icons up in our menu bar, giving us quick access to a variety of customization and productivity tools. Besides learning keyboard shortcuts, the difference between a casual user and an efficient power user is determined by the quality and quantity of various utilities, widgets and apps in their tech toolbox arsenal. We can't recommend all 18 (we're always testing/demoing apps), but we can personally endorse 5 of them to anyone and everyone looking to eke out a few more customized features from their computer...
Nocturne: if you're on your computer for any length of time beyond a few minutes, switching out to a darker desktop can ease eye strain (something Windows users can do without an additional app). Nocturne lets you take this idea even further, allowing you to change your display colors in various ways to give you a color scheme more suited to low light conditions (such as at night). We especially like the option to hide away our Menu Bar when inactive for an even more minimal appearance. (Free)
MagicPrefs: this is practically a must-download for anyone who uses an Apple Magic Mouse or Magic Trackpad. Tweak sensitivity settings, add gesture features way beyond the stock ones offered by Apple, and tame the wild beast known as the Magic Mouse. (Free)
SoundSource: a tiny menu bar app that allows you to switch your audio input and output sources and volume control quickly. We find it particularly useful when we need to switch from our external speakers to "keep it down, will ya!" headphones hour. (Free)
Alarms: minimal, unobtrusive and a trusty tool for those of us who need to be reminded of various small tasks throughout the day/week without an excess of bells and whistles. Like many of these utilities, Alarms hides away when not needed, but slides down to schedule your next reminder for quick updates, including files and URLs. ($15)
Divvy: out latest favorite utility was a recent Final Frame. The utility of Divvy becomes more easily apparent after you watch the video or try it out yourself, but in short, the utility lets you to designate how much space each window on your desktop will take up with precise control. If you're an app multitasker with 10 bazillions windows open at once and have a big screen, this could change your life for Windows and Mac users alike. ($14)
We'll follow up in the near future with 5 similar productivity and customization apps for Windows 7 and Vista users. But feel free to share your favorite apps and utilities you use daily below and maybe we'll add yet another to our menu bar gang.