My husband wants to build muscle, what to get for his Birthday?

My husband is in great shape but he wants to tone up. For his birthday he asked for Creatine, being in the pharmaceutical field I am not really fan of supplements of any kind, I've seen too many side effects. From what I know Creatine is ok in small doses but larger doses can effect the kidney and liver. So anyways, I don't know a lot about building muscle.... I know he wants something for his birthday to help this muscle thing so what's some advice? What would you get a guy that's trying to build a six pack and whatever else? Lol I plan on going to GNC tomorrow and asking one of their associates what they'd suggest but I wanted your opinion first (So I can sound somewhat intelligent). Thanks everyone!