I always have one of these in my pocket. The Leatherman Fuse (top) is bladeless, so I can carry it where even knives are not allowed. The bottom one is a Leatherman Juice CS4.
I also have one of these on me when I can. From top to bottom: Emerson Mini-Commander, Emerson Mini-CQC-7BW, Benchmade Mini-Presidio. The Benchmade is set up for left-hand pocket carry; it's what I carry when I also carry a gun.
On those rare occasions when I'm restricted to a 2" blade, I carry this Spyderco Chicago.
As for sharpening...well...
Even the oldest, most well-used knife in my collection, the Mini-Commander, hasn't needed sharpening. I've used that to cut everything from packing tape, duct tape, and corrugated cardboard boxes, and it'll still cleanly slice a sheet of paper.
I keep meaning to get a sharpening kit, but I just haven't gotten around to it. I used to collect knives regularly and used a Lansky kit, but that had to be at least 12 years ago when I last sharpened a knife.
While not a knife, I also carry a Benchmade Houdini keychain that has a seat belt cutter, LED light, rescue whistle, and window breaker.