The recent Seiko/ETA thread got me thinking about this- and I'll start by saying that I generally do not care about accuracy when choosing a piece. That however does not mean I ignore it in my current collection. In fact, I have noticed that some people get better performance from shared references than another member would. It is part of the beauty of the watch you own and love truly being 'yours.'
That being said- What is the most accurate (true mechanical) watch you own? For me, my Nomos Tangente is insanely accurate. I don't know if I am just lucky but it seems to regularly run within +/- 1 second in a 48 hour period. When I am not wearing it, it is face down and I wind it fully each morning.
I imagine autos and hand winds may have some variations, but all of that aside, I ask you- my fellow WUS'ers- what is YOUR most accurate mechanical watch?