I make my oatmeal with milk and then top with something that has crunch (fresh fruit, nuts, granola, etc). I like my oatmeal to have some 'chew'. I don't like adding milk after the fact because I don't like it wet, but most people I know eat it that way.

Cooking oatmeal with water leaves it so incredibly flat tasting that I only do it when it's my only choice.