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I just bought a logitech K360 which is wireless, and has a long battery life rating. Only $30. It's not "compatible with mac" but I made it work anyways with little difficulty using a prefpane I found thru google to swap the windows (command) key and the alt(option) key.

The prefpane called "DoubleCommand" which allowed me to swap the windows and alt keys when the normal mac keyboard prefs wouldn't work.
Then to make use of the labeled function notations on the F-keys, I downloaded quicksilver and using custom hotkey triggers, I made the home key go to internet home page, message key open mail, etc. To see how just search it on google.

You can likely do this with any keyboard--mac compatible or not. Just make sure the store you buy from has a return policy that makes it easy if you can't make it work.
 
It's not "compatible with mac" but I made it work anyways with little difficulty using a prefpane I found thru google to swap the windows (command) key and the alt(option) key.

The prefpane called "DoubleCommand" which allowed me to swap the windows and alt keys when the normal mac keyboard prefs wouldn't work.

Bizarre. My ancient Northgate Omnikey keyboard is so old it doesn't even have a Windows key, and even requires a pair of adapters to connect to the Mac, yet the standard Keyboard preference pane has no trouble assigning keys to make them match (in my case the Caps Lock key is mapped to the Command function which otherwise would not be obtainable.
 
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