For me, it's the 'trinity' of scissors - metal file/saw - inline phillips.
If the small blade is one of my favorite tool on a SAK, then Scissors is probably a close second, especially in an urban setting.
Metal file/saw, since it did once saw my behind on a long trip, and in a pinch, it could do what a wood saw does, but not the other way around.
Inline phillips, it's just so convenient, especially in a 4-5 layers SAK.