i find most of the 'pro-dynamic' stuff to be kind of well... not very impressive. and i say that as someone who primarily uses 'dynamic' languages. to be the big win for dynamic languages is the ability to debugger driven development but many dynamic languages don't have a debugger that will allow you to do that. i never really understood the power that 'dynamic' gives you until i started using lisp and smalltalk environments. ruby, as an example, is nice- i use it all the time- but it doesn't have the same power as a smalltalk or lisp w/ a serious dev environment- and that has nothing to do with the typing system.

with smalltalk, i can write a test, have it fail and from the debugger, add my needed classes, add instance variables, change variable values, check state, move back to previous points in the stack and restart after making those changes and continue on my way. once you've tried it, it is a very addictive and pain free way to develop. just doing dynamic typing doesn't give you that. it requires much more, in the end that is what really interests me. i find that to be far more of a productivity boost day to day than the stuff that these static vs dynamic arguments usually turn on.

As to people who stick to a single paradigm and tout it as the best thing since sliced bread well... except when I get a little cranky I don't have much use for that and try to tune it out as background noise.