I think it is a good question, and not something I ever thought about, but I've seen some amazing static discharges. Also, having had the house taking a direct lightning hit once, and the damage that was done was amazing. Anything that had a wire connected to it, and was electronic, got fried. I had the earphones plugged in on my Walkman and it was toast. My wife didn't have her earphones plugged in and her's was fine.
Currently, the lightning arrestors, A/C electrical ground, and all the re-bar on the swimming pool are all tied together. There are also copper plates buried in the ground on all corners of the house. I'd say I had a pretty good ground. However, a lot has to do with the conductivity of the soil.
One day in Vietnam it was raining and my feet were wet. All the equipment in the communication's center was grounded to a common ground - including the workbench that the teletype people had next to my safe. Well, someone had pushed the bench up against my safe. I went to get into the safe to get my Crypto books and got quite a surprising shock. I was an unhappy camper because I thought someone had rigged it to get me. However, when I investigated I found that between the Comm Center common ground and a mud puddle there was 67 volts A/C. There may have been even more when I got the shock.
So, if my house took another direct hit, what kind of voltage would be present on my common ground? I know there would be one heck of a current flow, and since there is some resistance present, there has to be some IR drop. I wouldn't want to be touching anything that is on that common ground bus at the time.
In other words: don't ground your press!!! Actually, if it is storming outside, don't be touching any metal objects anyhow.