Here's what I've been able to justify so far:

My keep at work and ride at lunch road bike (Late 90's Titanium MongoosePro Cipressa with DA 9-speed)
My Touring bike (1985 Fuji Touring Series V with barcons)
My ride with Kids and around the neighborhood bike (1971 Raliegh Super Course with trail tires, fenders with moustache bars + barcons)
My in the house fluid trainer bike (1988 Centurion IronMan Expert the only bike with DT shifters)
My Italian keep at home and ride on weekends road bike (90's Giordana XL-Strada with 9 speed Ultegra)
My hardtail Mountain bike (90's Titanium DB Racing)
Our Tandem (Burley Rock and Road)
Her road bike (1997 Bianchi Virata with 8 speed brifters - she's ridden it once)
Her cruiser bike (1980's Olympic 12 Nishiki Mixte with stem shifters)
Her Mountain bike (1993 Nishiki)
Our daughter's cruiser bike (1980's Bridgestone 300 Mixte with stem shifters)
Our daughter's Mountain bike (2006 Schwinn)
Our son's BMX bike (Generic garage sale find)
Our son's road bike (1980's Bridgestone 90 Jr Tenspeed with stem shifters)
Our two folding pack in the car and take to the beach bikes (twin Dahon Mariner 8-speeds)
I've also got a Mixte, and a Fuji Royale that I've committed to flipping but haven't had time to tear down yet, and the Bridgestone 700 that I loaned to a friend at work....I think I really may have a problem.