I've never named a vehicle... My friends have been known to name them for me, then I have to think hard when they talk to me in order to figure out what vehicle they are talking about...
My vehicles are:
The Cummins M37
The XM708 (sometimes known as "the little dump")
The M817 (sometimes known as "the big dump" - friends have been known to call it "tic-tac" based on the 200 or so tic-tac-toe games scratched into the paint on the inside of the cab...)
The XM813, (sometimes known as "the cargo truck" - friends have been known to call it "don't run" since it had "don't run" chalked on the doors by the folks at DRMO/GL when I picked it up...took a pair of batteries and a PCB to drive it off post...)
The Mule
The Jeep (M38 )
The Tractor (M931)
Sold last month, but I did have "The wrecker" (M816)
Others have been known as: the yellow M37, the blue M37, the grey M37, the Suburban, the Yukon, the 944s2, the 914, the 855 (aka "the little Deere"), the white Kenworth, the Red Kenworth...
You get the idea...