“Strunk and White said so” is not a sure-fire defense in a style argument.
SaysGrammar Girl in a piece for the NYTimes on the anniversary of Strunk and White's "Elements of Style." I used to do that back in high school when I first began to use it but I've mellowed down since. I still read it from time to time, like most of the other people in the NYT special, but tend to use my own style in writing.
I think Strunk and White's value is in erasing almost all traces of style, leaving one with an almost-blank state to begin with. As long as one remembers that language and the rules of grammar aren't set in stone (and even stone crumbles and weathers after a while), using the book is fine.
Just don't quote it like a (or worse, THE) bible of writing style.