i can't imagine having two fixed gear bikes. maybe if i was into fgfs but i don't think even then...

i have:
track bike
road bike
bmx bike

i'd rather have
nicer track bike
nicer road bike
cx bike
mt bike

i can see having a townie/cheap lockup bike and a regular, but as long as i'm going to have a whole bike dedicated to being not nice, it will coast at the very least.