Fish: Roger, Horace, and (dead one) Harry
Snails: Felix, Felix the Live (after the 1st one died), Guadalupe, and Frank
Tokay Geckos: Harry and Lloyd (from Dumb and Dumber)
Mice: Eugene and Gus
Snakes: Pliskin, Bosco, Mars, and Clyde
Some of these are mine and some are my roommates'. Oh, and the favorite normal-pet (i.e. dog or cat) name I've had was Calvin (a cat).