I've kept one specific personalized plate since the late 1980's, when they first became available in NY. "EZRDR". Easyrider for the phonetically inpaired. It has been on every Harley I have ever owned. Interesting story about getting it (2nd choice was going to be BOZO). Back then, you could reserve a plate for 6 months before you paid for and received it. It turns out, I called the DMV one day after someones 6 months were up. Never did learn what happened. Also, when I got the plate, there was a finger print in the paint. I will assume that is the person in a prison who made it.
I have a picture of that print somewhere. Just no way to run it.
Also, one year at Sturgis, I met Peter Fonda. He didn't really care about the plate. I think I bored him. I do have a good pic of us together, though.