I have named some of the cars I have owned.
1970 Chevy Impala: Liberty. I purchased it from a guy that lived in Liberty, KY.
1997 Nissan 200SX SE-R: Dot. It was one of ~700 200SX's made that year that was the Pacific Blue color and it reminded me of Carl Sagan's "The Pale Blue Dot" documentary.
2003 Acura TL: Sally. No specific reason, other than it just fit the personality of the car.
2014 Camry (current car): Pearl. It's painted in Toyota's Cosmic Mica Gray and it glitters in the sunlight, vaguely reminiscent of a pearl.
Just for reference, I'm 54 and have had a license since 1986. Liberty was my first car. There are a few cars not mentioned above, because I just never named them. The 200SX was the second SE-R I owned. The first was a 92 Sentra SE-R, which I liked a lot more than the 200SX, it just never got a name.
I still use a Yahoo account I created back in 95 (I think, it might be a little later).