The iMac has no buttons on the display for changing things like brightness, white balance etc. etc. So how is it done? I know osx has the brightness control of the display, and color calibration, but is that sufficient?!

Yup. You're forgetting that most brightness/white balance controls are software-driven anyway. The buttons on most displays are basically hotkeys.

F1 and F2 on the Aluminium keyboard that comes with the iMac control brightness.

Display preferences has your color controls.

control+shift+eject turns off the screen.

Another option is: System Preferences > Exposé & Spaces > Exposé and choose a screen corner for sleep display.
Now you can use your mouse to turn off the screen.

Very handy. Thanks!

Heh yeah, but that's extremely annoying sometimes. Like if you do it by accident and your screen turns off.

Never knew about that KB shortcut to turn off the screen. With an active corner, everything goes well though.

They really should ask in the prefs window about that main Power button on the back. Like : press 5 seconds and the iMac shuts down. That'll always be like that.

But press it once : Do you want it to sleep or to turn off the screen?

A radio button would do it in the Energy Saving pane.

Steve Jobs controls our Macs from his command lab and nuclear launch center.