seriously though thats a pretty broad question. it depends on what ur shooting. 1/48 shutter is what film cameras usually shoot at...so people like shooting at the shutter on the dvx in 24p. the higher you go the more choppy and sharp your footage with be.
low f numbers is if u want more shallow DOP (coupled with zooming in)..dont go lower than 2.8 on the dvx as resolution will fall off alot. However as u know with this wide of an iris ur going to need some ND in order not to overexpose.
So its really what just what u wanna shoot really or how u want to.