I like the way Virginia Tech's roster looks at quarterback. The Hokies have two older, experienced guys who can compete for the starting job. They also have two younger players with upside who will get plenty of reps, but who won't have to be forced into the action before they are ready. Tech's quarterback roster, which was almost entirely built by Scot Loeffler, is ideal.
Theoretically, every spot on the depth chart is up for grabs, in my opinion.