Why I chose Windows 7 over Snow Leopard (and you should, too)
betanews.com
betanews.com
If all you're using your OS for is some kind of browser hosting facility, then you can judge your OS by the chrome.
I think Windows 7 has some appeal here only because it's shiny and new and OS X is boring and old.
In the unlikely event Windows ever gets serious about their command line, then maybe it will be a viable development platform. Until then it's some kind of hilarious joke.
While Windows could get a useful command line interface, the whole design of the OS works against it.
Being Unix is not a prerequisite for the command-line being decent either. What makes a good command-line is consistency and power. For example the command-line on some cira 1980's lisp machines the command-line was the operating system. Then there is the command-line on OpenVMS.
I think Microsoft intends to get round some of the limitations you list by building commands into the shell and making the shell itself extensible. Parts of it look very unix/perl like: http://blogs.msdn.com/arulk/archive/2005/02/24/379732.aspx
Although I am skeptical, I'd welcome any move to make windows more usable and Microsoft has changed the game before in the past.
Market share is not always given to the best technology.