Though I too like the idea of getting the .357 for all of the good reasons previously offered by other posters in this thread, if, as you say, your dad is "Old School and the more historically correct in terms of ammo, the more he will probably like it" and he "doesn't reload which is a shame. He doesn't go shooting that much to really warrant it. Only time he goes is when I drag him to the range with me", then getting a New Vaquero chambered in .45 Colt might be the best option. He doesn't shoot much, which makes the cost of the ammunition a little less relevant, and he appreciates the historical significance of period correct ammunition-you don't get much more "historical" in terms of ammunition than the .45 Colt.
I, too, like the idea of the polished (pseudo nickle) s/s finish on the Vaquero with proper stag grips. It seems to me that your deserving father has good reasons to be proud of his son, FoxtrotRomeo.