"A language that doesn't affect the way you think about programming, is not worth knowing." --Alan Perlis

I think this is the point of the OP, obscured somewhat by the discussion of 3.3.1 (IMO). While in theory everything is possible with every language, each "worthwhile" language affects the way you think about programming. Idiomatic Ruby makes you think about extremely late binding of behaviour. Flash and Processing make you think about drawing on a canvas (in different ways!). Idiomatic Lisp makes you think about programs as data. And so forth.

I think it matters very much which programming language you use, and I can demonstrate this. Let's have a programming contest. You may choose what we are to build. You may pick a domain in which you are comfortable. I may choose the language you use, provided it is Turing-complete.