Lightning....as far as my experience is all about luck and taking a ton of pictures of black sky and hoping to time it right. I have had success by trying to time out how often the lightning is striking and taking bursts of pictures by holding down the shutter button.
Wildman, I have spent the last couple hours looking at your photos and I am feeling so inspired right now. Truly,truly amazing stuff. You obviously have a great eye, but also what a great camera you have. I'm jealous.