If the pages are static, then there aren't that many advantages. All the advantages you can get from includes, etc can be done with an offline batch processor.
But if you need to vary anything, customize things as far as user preferences, or just about anything else interesting, PHP is the way to go.
Don't overlook the possibility of getting the best of both worlds, by dynamically generating your static pages as needed. Steve Yelvington has posted an interesting and fairly detailed description of how some of the news sites do this; perhaps if you search on "news" you might be able to find the sequence of postings about this.
