Though this card doesn't have the hearts or cupids usually found on a Valentine, I see no reason why it couldn't be used as one. The sentiment is the same. There's no need to restrict yourself to common themes or icons when creating occasion specific cards.
Stamp: large image (PSX), small image (Rubber Stampede), sentiment (Stampin' Up)
Papers: white cardstock (Georgia Pacific), pink cardstock (stash), patterned papers (Basic Grey Perhaps), green vellum (stash)
Inks: Fresco Chalk Florentine Pink, Versamark, Distress Ink Bundled Sage
Accessories: green ribbons (stash), pearls (Kaiser)