First off, great thread!
I used to work for the Secret Service - protection for 43, our current, sitting president. I spent the majority of my trigger time during that period of my life with my issue weapon - SIG 229 chambered in .357 SIG.
While I truly believe shooting one gun consistently and often is the way to go for self defense and protection purposes, I also believe that inherently sound firearm handling techniques are leveragable across multiple platforms.
That said, since I'm a gun nut, I shoot a myriad of weapons quite often. However, I tend to go back to one for the majority of my self defense and protection duties because, much like you I'm sure, we all have favorites.
I was shooting yesterday at a relatively relaxed outdoor range in PA. An older gentlemen next to me was watching me shoot. He kindly approached and asked if I would shoot his .44 MAG Smith & Wesson revolver. I'm more of an autoloader fan but welcomed the opportunity, as I hadn't shot a revolver in years. I took 5 shots and hit a 5 gallon drum 3 out of 5 times (barely missing the 2) at 150 yards freehand. This was proof enough for me that trigger control and gun handling skills are portable to other platforms.
Anyway, best of luck. I say shoot often and achieve your own personal objectives with whatever you like to shoot.