It's really hard to tell without knowing what kind of person he is, as all the best gifts are either the personal ones that fit best for him, or the personal details between you and him that are best left unsaid.
Really, he'll like any gift you give him. As far as the sex-as-gift option goes, if that's really the neighborhood you want to browse, at least be creative with it. I mean, sending him a card with the panties you aren't wearing when he opens them is a neat gesture, but to really bring some meaning out of it, go with ideas like the coupon book.
One shared shower, if that's his sort of thing. A free back-rub, or a coupon for some free alone-time if he ever gets busy when you want to spend time with him. If you subscribe to the tao of "It's the thought that counts," then show you're being thoughtful. If he often has trouble keeping a hold of where he set his keys down, get him a key-hook. (Hell, make it yourself.) If he's a cat person, and has a lot of cats, buy one of his cats a brand new collar, possibly his favorite. If he's into gaming, see if you can get a spare case for the system in question, and make/have someone make a custom case mod.
But yeah, it's really a case-by-case basis. Just remember the few things:
- The gift most appreciated is the one that shows concern or thoughtfulness.
- The gift best shared is the gift given at the right time.
- The gift most enjoyed is the gift that lasts the longest.
Obviously, play it smart. That coupon book was a good idea, if you want to run with it. Just cater it to the things he complains about the most, or most often needs done.
And the cute stuff, honestly Susan, I'd ask you out just for that cake. =P