If I close my eyes I see the inner of my eye lids. Interestingly very intense visual stimuli can trigger mental images for me. I remember that when I closed my eyes after endless hours of Counterstrike, I would still see the game, tho I couldn't control what I see. Same goes for porn. Sometimes I remember my dreams, which are visual, but I don't think that I experience any other sense while dreaming. As kid I had lucid dreams, which I was stunned of, because of the amount of details I remembered. I just looked at faces of people I knew. Lucid dreaming is still something which I want to try to train.