When designing a war-strategy game, I am curious to the methods in setting up the diagonal grid commonly used. The simple solutions I have developed are either design two buffers one for the normal rectangular grid displayed with diamond bitmaps while the other buffer is used for a type of offset to the normal grid. The second solution is to use a rotational algorithm to rotate the screen, which could be consuming in future optimizations. What are the current game engine designs for Diamond Grids and the tiles?

you are talking about isometric graphics...
there are a bunch of tutorials on this website, in the "articles & resources" section...
also, there is another forum on here, called "isometric land"... see that one for lots stuff about this...

--- krez (krezisback@aol.com)