Brad Goreski shared his Valentine's Day fashion "thoughts" with Lucky magazine and suggested a good gift for the "fashion guy" is "something stylish and timeless – like cufflinks or a watch.” These cufflinks were featured in Lucky's blog post about la BFG (Brad Friendly Goreski or Big Fashionable Giant).
I also was thinking about this question today and if you truly have a fashion-forward boyfriend, you could buy him something kind of unisex that you could wear too. After all, when you dump him, you'll need a souvenir. Boyfriends are ephemeral. Fashion is forever.