If you're shooting s16, you probably already know exactly what you want and exactly what you're doing. But when you're out in the field, there is always a bit of of 'fluidity' to the situation—locations aren't exactly like the scout dossier said, the angle is a tiny bit too wide, the sticks can only extend just a few inches further.
For these situations, having a versatile zoom is the way to go. From run-and-gun to agonizing retakes on a tripod, not having to even think about lens changes can be the difference between a tough day and an impossible one.
For exactly this, we've set up our XTR with a nice, wide canon zoom, which is a perfect match. If it's good enough for him, it's good enough for us.
If you're feeling like you want something a little more robust for dailies, we can even set up the PIX240 with it so anyone can see what's in the can without, well, opening up the can.