Lots of regrets, but three come to mind.
#1 S&W 686 Mountain gun
#2 Freedom Arms .454. Sold to an internet friend, and fortunately he sold it back to me for what I sold it to him for.
#3 the four I just sold, 2 being customs, 1 Bowen, and one with Roy Fishpaw custom grips. BUT, I sold them to pay for a 5 day Mountain Lion hunt in Arizona with hounds on horseback. Being a big rider and past hound hunter, this is my dream hunt.