Hmmm.my "go to" bike is the next one I am going to ride. The last bike ridden was my "came from" bike. (They can be the same.)
My bikes have different purposes. Yes, there is overlap, but often the ride decides the bike. Or just how I am feeling that day. If I want to go high-end, to I go geared or fix gear? (Same choice if I want to take a winter/rain/city bike.) And I have an old Raleigh Competition with geometry from 80 years ago. Classic double butted Reynolds 531 so a fine ride but nothing like any modern bike.
I've settled into these 5 bikes, probably for a while since they are all fine rides for their respective purposes, work really well, fit like dreams and are fun rides. And very different. (I sometimes get out on the driveway and realize, no I want to ride "that bike", go inside and swap bikes and shoes.)
Ben