As I have gone through the 30 Days With Ubuntu Linux experience--and especially the past couple days as I have toyed with Wine and trying to get Windows software to run within Ubuntu--I have seen ample evidence of the security features of the OS. Simply put, Ubuntu Linux (and, I assume, Linux in general) is more secure by default.
That may seem blasphemous coming from a devoted Windows user. The reality is what it is, though.

Here is what I have seen. First--the OS defaults to a timeout of sorts that requires me to enter my password again to wake the system up if I step away for more than a minute or two. Every time I want to make a change, or install some app from the Ubuntu Software Center, I have to enter my password again to grant permission--a' la the UAC function in Windows.

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