What I did for my husband is I made him a Tshirt, but he is not one of those sappy guys who will wear Tshirts with pictures and writing on them. So what I did is I bought a plain blue Tshirt (his favorite color) with a pocket on the front. With fabric markers (the 3D kind) I wrote "I (heart) Dad" on the pocket. That's the extent of the writing so it's limited to the pocket and not overwhelming. Then with a sponge brush I covered my daughter's hands and feet (one at a time) with fabric paint and stamped them on the back of the Tshirt. He absolutely loved it and actually wears the Tshirt all the time.
My girlfriend's husband is less aprehensive, so she bought the computer iron-on paper. She printed a picture of her daughter on the iron-on paper and also printed a poem she wrote for her husband. She then ironed them onto a Tshirt for him. It was incredible. She did a really great job.
Another great idea is stepping stones. You can get the kits at any craft store, and they are really easy to make. We did those after my son was born, one for each kid, with a handprint and a footprint for each, their name and the date. He really loved those. They are still in our garden today.