Terry,
If there is anyone here that does not admit to something like that happening to them at least once, they are either lying or have never changed a spark plug.
I've found the best technique (at least on my SPF) is to jack up the front end first. I make sure the car is in gear (my parking brake is crap). I use a small swatch of carpet on the jack to maximize clearance and minimize scratching. I then jack up the front end and place two jack stands (on their LOWEST setting) under the front frame rails. I then proceed to the back of the car and my floorjack barely wedges between the shock mount and the gas tank. I lift up the back end and do the same (two jack stands on their lowest setting, right on the frame rails). I then go back to the front and raise the car enough to increase the height a couple notches on the stands. Then to the back and repeat until I'm satisfied.
This technique adds maybe 5 minutes to the process, but it's safer and always yields the best results for me.
-Dean