Not too long ago I surprised my husband by taking crayons (the wipe-off type) and writing messages on our shower wall.  Of course, "I love you!" was one of them.  Also I made a big heart and wrote in it "You are..." then below those words, in the heart I listed all the things he is to me... "A wonderful husband", "Romantic", "Sexy", "My forever love", etc...  My husband thought this was a wonderful way to show my love for him.  I haven't yet washed the writing off the wall and he still enjoys reading it.