I use a Chef's Choice 360 diamond hone. It's a manual two-slot thing--slot 1 sharpens, and slot 2 hones. I've used this sort of thing for years (needs replacement every so often), and even my oldest knives have maintained good cutting edges. I like it!
Now I'm sure that someone is going to pop up and say that I should just learn to use stones and do it properly. Let me say that when I was about 12 and tried to learn this, my dad/teacher went absolutely ballistic and screamed
at me for ruining the edges during my first lesson.
Haven't tried since, and I'm not gonna.
And the professional sharpening guy around here is a person who does lawnmower blades. He says there's nothing to doing kitchen knives, too, but I've seen his work, and I think he takes off too much metal.