I got my boyfriend a bag for uni. It sounds lame, but he used to take this enormous sports bag with him everywhere, which weighed a ton and had absolutely all his books in it, all the time. Then I left one of my enviro-bag things over at his house and he carried his stuff around in that, but it was pretty close to splitting. Being a good retrosexual, he didn't want to buy himself a new one, so for his birthday I got him a dark brown messenger bag with a pattern of squares in muted colours on the top and heaps of pockets on the outside. He really seemed to like it, and he's been using it ever since.
Though really, you can eschew the material stuff and spend money on a nice time instead - take him out to dinner somewhere new, book a dancing lesson, have a bbq with his family, organise a picnic with his friends where you do the cooking, or go hiking for a day, depending on what kind of stuff he likes doing. Baking and decorating a cake goes down well, too.
And going down goes down well as well.