In town if I'm too lazy to put on a proper holster and Glock up, I'll slip a 642 in my pocket with a Blackhawk pocket holster. In my pocket right now, had to run up the street to the drugstore.
Out in the country on private land, I usually tote around a Cimmaron Model P in .45 Colt. I do have field type holsters for my 28-2, my 1917 and even my .38 M&P in a pinch. The Cimarron is my go-to though, 'cause to me "woods gun" means big bore single action. Just feels right.