A carbon fork will help dampen vibration, but not shock. It can make lips and small cracks in the pavement more tolerable, but won't do much/anything for a pothole.

I bet a metal fork with a J-curve at the end would give a similar effect, and might do a little more for actual shock. The curve in a fork turns it into a bit of a spring, letting it flex a little bit.

Also, cork bar tape is really nice, and, if you're suffering the slings and arrows of substandard pavement, Fizik makes gel strips that go on your handlebars, under the tape, to soften things up even more. Some people wrap their bars in two sets of tape.