Every day since sophomore year of high school I've carried either my victorinox Swiss tool (their version of the leatherman) or a leatherman wave. I also carry a pocket knife. Recently it's been the Kershaw Emerson partnership tanto with the Emerson wave feature. Excellent knife that opens as soon as you pull it out of your pocket.
I carried an Old Timer for a lot of years. Before that I had a Boy Scout knife I carried since ... I can't remember that far back.
These days I've got a Swiss Army knife.
My daily driver (at least when I am working or camping and need handy cutlery in my pocket) is a Gerber Tactical. Its very thin and light weight when folded, but a really sharp and substantial cutting tool when its open. The configuration of the blade and the pocket clip is optimal for me, especially when I am working out in the field. However, I know that Gerber is not a high quality knife. And I know it will require some serious blade maintenance from time to time.
My knife of choice when it counts... when I am doing some serious hiking or backpacking, is a Buck 110.