Maybe it is the boy scout in me, but I've carried a knife with me since I was 8 or 9. Never to school, but always with me. Now people look for me when we are places and need a knife to open something or what not.
I carry the knife below everyday. I have many others in my collection, but this one is special because it was given to me by my Scoutmaster as a high school graduation gift. (I'm also an Eagle scout.)
I just bought this CRKT "Pikes Peak" on on sale, half-off, Saturday for my girlfriend:
And today, Sunday, I looked at buying one of the following because I want to carrying pliers and a knife with me all the time, but my Gerber multi-tool is too big. I couldn't decide which one, so I am going to go back later this week:
Leatherman Freestyle
OR
Leatherman Skeletool
I am also a fan of older Swiss Army knives, and CRKT (Columbia River Knife and Tool), Gerber multi-pliers (over leatherman because you can just flip your wrist and the pliers come out), Kershaw, and Boker. I like the more expensive stuff, but there is nothing worse than have a dull knife when you need it.
Also, to those that use their knives everyday, I know what you mean when you need it. I worked construction in college and while we didn't have a uniform we were ALWAYS expected to have our tool belt, tape measure, pencil, hammer, and utility knife. (I used my pocket knife at first, but the blades would ruin too quickly, so a utility knife is much better for such purposes.) Out of those items I can say that I used the utility knife probably more often than any of the other "tools."