IGNIGN has a slew of hilarious valentines on their website. They also have a lil' app up that makes it easy to send via email, share on Facebook, Twitter, etc. Below are some of my favorites.
AMC - The Walking DeadAMC has a few Walking Dead e-cards you can send that special someone. I mean, I personally find nothing more romantic than discussing zombie survival plans over a glass of whiskey, so I'd say these are a safe bet. <3. (Because everyone is like me, right?)
PokemonYou simply can't go wrong sending your valentine something that has the name "Poke" in it, if ya catch my drift. ::nudge-nudge:: (I'm so clever.)
Portal/L4DThe Mary Sue still has a great selection up from last year.
ZeldaThere are hundreds of Zelda valentines out there, but don't worry, I've already looked through 12% of them. Therefore you should only use the ones I found. I promise you they're the best.
And if none of the above are suitable for you, then all I can say is when you're sitting home alone tonight stuffing your face full of stale chocolate you'll regret not choosing one of the hand-picked Blonde Nerd approved valentines. As for me? I'm heading to Vegas. Nothing quite screams "ROMANTIC!" like stumbling your way past wedding chapels at 4:30 in the morning.