I was trying the previously posted tip on adding a command key to the "Hide Others" menu item, but it didn't seem to work, so I did some poking around, and came up with this set of instructions.
Read the rest of this article if you'd like the 10.1 method of adding a "Hide Others" keyboard shortcut.
[Editor's note: I have not tried this myself yet...]
Fire up the Terminal, and enter these commands:
cd /System/Library/Frameworks/Carbon.framework/Versions/A/Enter your root password to confirm.
cd Frameworks/HIToolbox.framework/Versions/A/Resources/English.lproj/StandardMenus.nib/
sudo cp objects.xib objects.xib.old
<string name="keyEquivalent">h</string>When you are complete, the section should look like this:
<int name="keyEquivalentModifier">1179648</int>
<object class="IBCarbonMenuItem" id="260">Save your changes, and restart your computer.
<string name="title">Hide Others</string>
<string name="keyEquivalent">h</string>
<int name="keyEquivalentModifier">1179648</int>
<ostype name="command">hido</ostype>
</object>
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