Casey
Sean's right -- you need to pick the f-stop for the effect you're going after. However, I understand your question and I'd answer that I try and keep the depth of field low most of the time. I find that f1.4 - 2.8 is pretty narrow -- so I keep that for beauty shots. I usually use F4 - f5.6 for general shooting.
Remember that depth of field is a percentage of the subject distance. When you're 1 meter from the subject, f1.4 can even get you only one eye in focus if the model has her head turned. If you're 3 meters away, you'll have the model's entire face in focus.
Bob
Something at f1.4 and 1 meter or closer.
