It varies, but lately the most handled and dry fired guns are:
-My Taurus 85CH. It is most accessable as it is always at hand and loaded (it is my "always" HD gun). It is already at hand (either near me when sleeping or in my pocket or holster when awake and at home 99% of the time) so all I have to do is open the cylinder and dump the rounds and I can dry fire all I want. Also, it has one sweet DAO trigger.
-My Taurus PT140 Millennium Pro. It is also always at hand as it is an "always" HD gun- it is nearby when sleeping and often in a holster around the house. Just drop the mag and remove the round from the chamber and I'm ready to go. It is also one of my current favorites and feels great in the hand so I like to handle it a lot.
-My Charles Daly 1911. If you own a 1911 you'll understand.
-My S&W 57, from the first year of production. If you own an N-frame you'll understand.
-My Winchester 94 in .45LC.
Wow, I didn't mean it that way, but the list came out pretty much in order. This group of guns gets handled several times more than the rest of my guns put together (heck the top three get handled around 2 times more than the rest of my guns put together).