From all that I can tell, Post Cereal is one of the good guys.  I may have overlooked one of their brands but from what I can see, none of their cereals contain HFCS.

BUT, their Honey Bunches of Oats does contain artificial flavors.  I guess I can’t have my cake and eat it too.

For the most part, I think Post is one of the good guys, they were the only one I saw on the shelf that had a box of cereal that said No High Fructose Corn Syrup.