Being from the upper Midwest we have always resorted to flying. I've toyed with the idea of driving but that had always meant taking an extra few days off of work to accommodate the 20+ hour drive to & from the FL. cruise ports. My wife can't drive anymore, and back problems prevent me from driving for more than 6-8 hour stretches per day. Not that I wouldn't enjoy the drive, it's just always been the time factor. Also, once I factored in the extra costs (gas, hotel rooms, meals, etc...) flying has always ended up being more cost effective anyway.
We always fly in the night B4 embarkation because I'm too paranoid about flight delays and/or cancellations to risk flying in the day of. This topic suggests perhaps adding in a second day for peace of mind, which of course means an extra days hotel stay, meals, etc..... While I agree that it would probably be a prudent move until the airlines get their act together (if that ever happens) IMHO that'll mess with a lot of peoples budgets.
As for us, now that full retirement is on the horizon I'm able to take off for a longer periods, so I'm considering driving to Galv. for our cruise next spring. We are also considering relocation to a warmer climate, and close proximity (max 6-8 hour drive) to cruise ports will be a factor in our decision. I'm currently thinking the FL panhandle (Pensacola area) could put us within driving distance of 5 or more major cruise ports.