Get something that he is interested in. I've gotten my partner customized jerseys for his favorite teams, tickets to games he'd like to see and have even gotten him gift certificates for things he'd like (like a massage!).
Consider finding out maybe what his favorite bands are and do a little research into whether they might be touring locally and then purchase him tickets for the show.
Depending how long you've been together, it could be a variety of things. I'd buy something pertaining to his hobbies. Men also seem to like weird gadgets.
