Well, since this is plural, with no need to narrow it down to one: SIG P229, Ruger GP100, Speed Six, and SP101, Les Baer Thunder Ranch Special, Seecamp LWS-32, S&W L-, K-, and J-frames, and the Colt Single Action Army and its better derivatives.
I use SIG P229s, in .40 S&W, for police duty and 99% of my personal-time carry.
My agency requires us to buy our own weapons, mandates certain .40 autoloaders, and I am GLAD and GRATEFUL the P229 is on the "approved" list.
My single most favored individual handgun is a particular 4" GP100, which was my duty handgun for a while, notable on a very interesting night in the summer of 1993. Bidding starts at $15K. Just kidding about the bidding! Not for sale.