I've carried one every day of my life since I was about 14 or 15....it's just the way we grew up. Anyway I rotate between several pocket knives but lately it's been a CRKT KISS Assist with the non-serrated blade. It's a great EDC, very thin and light and the assisted opening is as quick as an automatic. Not expensive either, as I recall it's around $50.
I prefer my Tac Force Bear Claw Assisted Knife for non work functions. But the pin that keeps the blade from folding too far out is gone, I need to get one machined at work to replace. My EDC for work and such is my Mtech 440 steel. Nothing fancy. but it does the trick.
I carry several knifes everyday. 2 are SOG twitch XLs. One has a straight blade the other serrated. The straight blade is as sharp as I can get it and it is for protection only. The other is used for everyday use ( cutting plastic at work, tape, paper etc). I also carry a tiny little tooth pick type that I use to strip wire.