My GMC is named Harvey, after the big white rabbit in the Jimmy Stewart movie, because they're both heavy drinkers (and we keep finding rabbits near the truck). My wife's truck is BlueHawk, because the day she drove it home from the dealer a big hawk flew down the road alongside her for several miles, and the truck is blue.
My previous truck was an old TV news truck, an E-350 with the 460 engine, painted dark grey and named "The Beast"
The wife's previous truck, which now belongs to her step-dad out in Idaho, is named Benjamin.