For years I only had one bike, luckily it is a late '80s Explosif. I got it in the early '90's, and used it for everything. I have commutated on it, ridden off road on it, stuck panniers on it and toured with it (I even used it to ride from Tel Aviv to Cairo) and for a short while I worked as a courier on it in London.
During the years it has undergone a couple of rebuilds, and now is undergoing another, pics when it is finished (hopefully).
Riding any of the other bikes just makes me want to ride the Kona, but money is tight, so the build could take a while.