get to know what his interests are; focus on that twice as hard next time you're with him. guys also seem to hint at stuff like this; notice if he constantly talks about a certain something he's "always" wanted. you can also find out by casual conversation. say things like, "what's you favorite store?" and simply tell him your favorite and why. you'd be amazed how much you can find out about a person's interests through conversation.
Video games, movies, music... toys?
Any electronic will do :PChristmas present
Gift cards!!!What to ask for for Christmas