For a while I called my 85 mm 1.8 "the walrus."
No particular reason, I just wanted something random.
It didn't stick.
The only lens I've got that goes by anything other than its focal length is the "kit" lens 18-55 4-5.6 non-IS. Believe it or not, mine is actually sharp.
Arrgh, I don't know why it bugs me, but the Tokina AF 193 - 19-35mm f/3.5-4.5 is the "Plastic Fantastic," has been for years on lots of boards in several different mounts. and the "Nifty Fifty" is the "Nifty Fifty."