All of the above, and any other normal wear bits you'll have to pull in the process. Here's a link that gives some insight into the whole timing process, if you plan to do the timing belt yourself, or even if you have someone else do it.
I just got mine back from the local ford dealership after bringing it in for a new timing belt, pulleys, and drive belt, and while the tech had it apart, I bought some new plugs for it, and had the valve cover sandblasted and repainted.
Of course, this could be just the excuse you need to get some performance bits too, "while I'm at it." [