Jon:
I use both hard cases and gig bags, depending on the situation. When I go to rehearsal, I find it very convenient to slip a gig bag over my shoulder. Of course, this is a situation where I'm the only one handling my guitar and it's only going to be transported in my vehicle to and from the studio. Gig bags are also very convenient if I'm carrying more than one instrument to rehearsal. The one place I NEVER use a gig bag is on a gig! If my guitar is going to be transported along with a bunch of other heavy stuff, and may be handled by someone else, it is in a case. period.
Another situation that might call for a gig back is flying with your instrument, assuming the airline has o.k.ed you to carry it on board.
My $0.02 ... get both and adjust to the situation.
Bill, the guitar one
(Message edited by lbpesq on July 05, 2006)