I have seen and driven worse but I am with CrazyD i would worry about the pickup.

The pickup can be very low and near the bottom of the pan. If the dent is bad enough it could crack or close the pickup area.

Not worth risking it.

Once it is off a couple smacks with a sledge and 2x4 and the pan will be good as new.
The pickup would be very suspicious to me. Most bad dents i encountered bend it at where it threads into the block. Easy place to crack the pickup there too.