Here is a list I created after seeing Brandon's list: Excluding the first one listed these were over a 5 year period.
Gremlin's Tricycle (this one rocked when I was 4)
Trek 1000 (did an Ironman on this)
Guru Racelite (First step into carbon)
Litespeed Pavia (made me want to leave carbon)
Litespeed Sienna (Ti is fun ride..but overpriced)
Xlab Mach 2 (first Tri bike)
Cervelo Soloist Team (Awesome bike)
Motobecane Super Mirage (70s steel bike)
SR (another early 80s steel bike which broke my collarbone and head)
Cervelo P2C (first fast tri bike)
Cannondale Slice (second fast tri bike which I love)
Cervelo R3-SL (the holy grail of road bikes)
I had 2 MTBs which sucked since I suck at off road stuff
After making this list I have a feeling I may have a bike fetish...
Care to make your list?