I hve a leatherman wave. My second after giving away the first. It's too heavy to keep in your pocket but a great way to take a minimal essential toolkit when travelling and you need to keep weight and size to a minimum. I rate leatherman much higher than Gerber, but have heard good things about the bigger heavier swiss army multitool.
I'm another who finds the Wave's diamond file to be a useful tool but if you're thinking about "every day carry", far and away the most useful tool is a quality small, light pocketknife that you can open, use and put away single handedly. That's the tool that gets used day in, day out more than any other and the ability to open and close it with just one hand makes it far more useful than a swiss army knife.
I'm another who finds the Wave's diamond file to be a useful tool but if you're thinking about "every day carry", far and away the most useful tool is a quality small, light pocketknife that you can open, use and put away single handedly. That's the tool that gets used day in, day out more than any other and the ability to open and close it with just one hand makes it far more useful than a swiss army knife.