It all depends upon your situation and your circumstances. For instance, a saw, while very useful when in forests, is not nearly so worthwhile above timberline. I carried a Tinker for many years, and found it quite adequate, although now I usually tote a much heavier Leatherman Wave-I really like having needlenose pliers handy (mostly because they are useful for opening jammed locking carabiners).

Any sharp knife is better than a dull blade - maintain whatever you carry.