I call my Ruger 4 5/8" .357 Vaquero my "Irrational Gun".
I often play a game with myself called "Why would I sell it?". Basically, it helps me mentally note if I really truly love a gun enough to hang onto it if I need the money or a trade comes up.
I have often talked myself into what I would let my 1911 go for or why I would trade a carry piece FNX away for something similar or why the .380 stuffed in my belt should be replaces with something that would hold the same 6+1 and do the same thing, etc.
I honestly can't think of a reason to ever get rid of my NV .357. Its my favorite caliber, my favorite revolver action, my favorite barrel length, and in my favorite finish (glossy stainless). It's not particularly GOOD for much. As a defensive weapon it's kinda slow (though I pack it from time to time). As a target or hunting gun it kinda sucks having fixed sights. I certainly get more performance out of my 6.5" Black Hawk of the same caliber.
That said, she's such a fine arm. Honestly, I dunno if I could ever under any circumstances give the NV or my SP101 up. Sure, I might pick a 9mm autoloader if I want to play the "there can be only one" game if we're talking about civil unrest and all the silly things we muse upon.
However, as a plinker and a robust gun built for the ages, the 4 5/8" NV just might be my favorite gun.