My site is very extensive and has more then 100 pages. The links through out the site to the other pages are all graphical in nature thus allowing me the opportunity to alt tag each button on each page. Lots of tasty opportunities to add keyword density. Now then my dilemma is how to best take advantage of this. Do I alt tag each page to raise the density of the target keywords on that page or do I make the alt tags add relevancy for the page they point to?