Best keyboard mapping approach to make a Mac work like Ubuntu? Through the day I work on both a Mac and Ubuntu.
What's the best option for mapping the Mac keyboard (an external, non-Mac one) to Ubuntu style keys - when using the Mac (OS X).

Basically I want to have:

Control on keyboard to trigger Command ⌘ keystroke on the Mac
Alt on keyboard to trigger Option ⌥ keystroke on the Mac
Windows on keyboard key to trigger Command ⌘ keystroke on the Mac

Aside from whether this is a good idea or not and which one I should pick, I am just posing the question of how to make the Mac, when used with the external keyboard, to be more Ubuntu-like.  My biggest interest is in making sure that vi/vim/macvim and tmux, both of which have a large number of keyboard commands, work the same for my fingers.

I initially thought about this posting on Ask Ubuntu but it actually seems more suitable here.
Ok, what you want to do is remap your modifiers:
Go to System Preferences and select Modifier Keys:

Then swap Cmd and Control.

note: in the shot they are not swapped
For reference, I do this with an external Razer Blackwidow for Windows (I want it to be like my Mac keyboard because I've been using Mac keyboards for 10 years).