My most used bikes have names from Don Quixote. It's one of my favorite pieces of literature. The whole crazy-old-man-riding-around-on-an-old-broken-down-horse-which-he-thinks-is-the-most-magnificent-beast aspect really hit home for me, a while back.
Doņa Molinera "Molly" (prostitute who plays along with Seņor Quixote's delusions and "knights" him in the first chapter) - This is my new commuter and goes against the "broken down" part of my naming scheme. She's a 2008 Fuji Touring.
Rocinante (Don Quixote's horse) - This was my commuter up until this past Fathers' Day. She's a 1983, Austro-Daimler mixte and my wife calls her Rosie.
Dapple (Sancho Panza's donkey) - This is one of my grocery shopping bikes. She's a 1986 Raleigh road bike with baskets and a hitch for pulling my home-brew trailer.
Freeride - A 1987 Miyata that I built up using nothing but dumpster and curb-side trash salvages.
Special Ed - My Specialized HardRock. You can probably figure out where the name came from.
Big Red - The 2007, New Belgium Brewery special edition Felt beach cruiser that I won in the Urban Assault Race.