On my Spydercos, the compression lock. Such as the one in my PM2 and SuperHawk.
My next favorite one is the liner lock on the Military, but only due to the huge opening (meant to be used with gloves) since I can easily work it as a lefty (my Mili is a standard, right hand model).
Always carry two. A main/larger blade (primary), and a smaller one (backup). The backup is also the one that comes out during normal office duties, since it is less "scary" to non-knife folks.
Primary is either a CF M390 Military or a SuperHawk. Backup is most often a ZDP-189 Dragonfly 2.
By far, my best impulse buy was when I got my Military (CF M390). I always though it was just too big - way too big, but after getting it and using it, I am sold on it!
My worst impulse buy was the Spyderco Assist. It just did not feel good in hand to me at all. I returned it the very next day.
From their respective specs, I knew the SuperHawk was a little smaller (but wider in the pocket), but I needed the reference to something I own and carry as I don't find the Milie too big/large. These photos are exactly what I needed - thanks much :D
My current EDC is an M390 CF Milie, but I am interested in finding a SuperHawk to split EDC duty. Can somebody please post a picture of a Military (any model) next to the SuperHawk so that I can get a better appreciation as to what to expect if/when I find one?