Hey Mcgirr..great question and one I've been wondering about myself.
Interesting to read everyone's answers and I reckon that all have answered in a perfect way that shows just how individual we all are!
I've got some great ideas now for what to do with my own car. I think that I'm going to stick with the standard suspension, until its time to change out due to normal wear and tear, then go for it on what set up I'd really like. I guess the test of the standard set up will be our trip to the Cape this year! Nice to know, Mcgirr that you've not only taken up stock cars but others have as well!
Its the one thing that has been bugging me that most people are quick to change out suspension on a brand new car. But as D4D has pointed out, with additions like bars, lights, batteries and the like, a car suddenly gains a lot more weight than it had as stock. I am yet to add all that!
On the airbag side of things...what kind of expense do they come to and are they tough enough to handle lots of dirt roads? (I'm thinking that this is a good way to stop the slight sag with the trailer on and not have to suffer changing the current suspension straight up...would that be correct?)