"But are its rules the be all and end all of writing? "
White's original, from before Strunk updated the book, is available for free online: http://www.bartleby.com/141/
Of course not everyone is celebrating, but even if you just want to argue about fine points of grammar, Strunk & White is a great place to start.
For more detailed questions of grammar, I point my students to Ken Wilson's Columbia Guide to Standard American English (close to 500 pages of advice) and the Guide to Grammar & Writing, a site started by Charles Darling in the early days of the Web at what was then Greater Hartford Community College.
(I knew both Ken and Charlie when they were alive, had great respect for both, and was charmed to find them both online.)
For more journalistic style and grammar issues, I suggest Gerald Grow's http://newsroom101.com