Birthday ideas for my boyfriend?

My boyfriend is turning twenty in February. Awhile away but I'm starting to plane early. I already know I'm getting him a silver chain for his wrist, some nice cologne, and one or two plain tee shirts. Is there anything else small I could get that he might enjoy? Also, I'm planning on baking a cake and decorating his room and such, any ideas for that besides balloons and streamers? Thanks =)