I think good design is intuitive but should also involve a certain degree of exploration (unless it’s.. say an ATM machine in which case exploration is not necessarily appreciated by the user). There’s a growing trend amongst designers though to use icons that are extremely hard to understand with the sole excuse that the use will eventually learn their meaning.

Joshua Porter makes a great case for labeling your icons in Labels always win.

However, I think labels should be kept around in almost all cases as they turn guesses into clear decisions. Nothing says “manage” like “manage”. In other words, in the battle of clarity between icons and labels, labels always win.