i've got:
- road bike
- mixte
- xtracycle (aka my minivan)
- cross bike
- the rear half of a tandem
- my husband's old road bike which resides at the in-laws' cottage in michigan (which will hopefully be replaced this summer by a cross bike instead because of exactly what Zen said earlier in the thread about skinny tired bikes and dirt roads - i want to expand my riding options up there!)

i feel like i've got pretty much all my options covered, but it doesn't stop me from coveting other bikes. i'd especially love to add one with s&s couplers.