Ahh, a fun one.
Freja, our awesome pit bull/rotweiler... I call her Frej (pronouced kinda like Fry), baby dog, and on rare occasion, stupid.
Lady, our mutt. Stupid, moron, dumb dog, funny looking. (I know, it sounds mean...)
Hercules, my brother's akita/rottweiler (huge dog...) - Herc, big guy, buddy, stinky, big buddy
Riley, my sister-in-law's... something dog.... Dingbat Dingo, dingo, stupid dog, idiot.
The ones that are dead had the really interesting nicknames, though