I did a single jump when I was 19, back in 1984. Very similar to JoanieBelle's experience. Static line, solo jump from around 3500 feet. We spent a few hours going over what to do when you jumped: start a count - "one thousand, two thousand, three thousand, four thousand, check canopy!" At "check" - look up and ensure that the canopy is fully deployed, and if not, jettison and pull the reserve. We also practiced how to land all graceful-like.
Well, when the time came, and I was smacked on the leg to jump, I hesitated a couple of seconds then let go. The "count" just disappeared from my head. "Whoooooaaaa!!!!" was more like what I did. There was just no rational thought at all, initially. After a few seconds, I thought maybe I'd better look up and check the canopy - and all was well. (It was actually very similar to my first practice spin in an airplane - all the training popped out of my head the very first time, but subsequently it all came back.)
We didn't have any radios - just a guy down on the ground with a huge bright orange arrow that he could move around on the ground. I had to look at him and turn in the direction he was pointing. It worked out pretty well, and I landed within a couple of dozen yards of the target. (It was out in farmland, and the next field over had a big pig wallow in it - didn't want to end up there.)
Anyway - all in all, an amazing experience. I've never done it again, but mostly because of expense (at the time) and taking up other hobbies (once I got more disposable income.)
Now bungee jumping - that I've done twice, and I need to get out and do that again!
That's me on the left, using some scary old military surplus parachute, and a very flashy early-80's jump suit. Stylin'!