I have a variety of EDC knives that I carry mostly on however I happen to feel that day. Occasionally I will do so with a specific purpose in mind (for example, on Friday I carried my SAK because I had a specific job to do that day and knew it would come in handy), but generally speaking, my daily use is light enough that I don't worry too much about it.
Most frequently, I carry a Spyderco Endura, and second most frequently is any of the five mini-trappers I have or a Spyderco Kiwi. The Kiwi is my newest slip-joint, and the more I carry it, the more I like it.
I rarely carry more than one knife on me, but if I do, I am a little more specific. I usually carry some sort of locking folder (typically my Endura, but I also have a Persistence that I really like) and my SAK. That makes for a combination of pocketknives that's pretty hard to beat short of carrying a multi-tool. Still, I rarely do that.
I also have a variety of Benchmade, Buck, Boker, Victorinox, Fox and various other knives that I rotate around. Part of the fun of the whole "knives as a hobby" thing for me is the fact that I can carry and use so much of my collection!