The Japanese, being avid MMOers, have got the mechanics right, you receive some chocolate on V-Day, then reciprocate on white day. Everyone else though does it the American way. Buy tons of shit, receive nothing. While the staples of Roses or Tulips (Thank you Delia for enlightening me on flowers) and REAL Chocolate are fine, the idea that it's all about women is wrong. It is a day to celebrate LOVE, not wizard sleeves. You guys need to get some +30 Balls and let the girl know you love her, but you expect the sentiment to be reciprocated. Otherwise it's more of a Quest with no reward than a 2-man raid.
Take your other half to a restaurant, but make your house the main event, flowers, candle lit movie, some glade air fresheners. Take her out to dance but don't dry hump each other, do a REAL dance, a dance that actually takes classes and daily practice to perfect. It may not sound like much, but I want you (if you have a partner) to try to waltz out of nowhere. You'll see that you will dance like shit because you aren't coordinated, the coordination and cooperation from dancing will definitely strengthen the bonds of your relationship. It's a 100% chance that you'll get to know your partner on a deeper level than before.
As for the ones just out for the kill (Oh you PvPers you), fuck it go for the easiest you can get away with. No need for Dinner and a Movie, McDonald's and a DVD should suffice.
All in all I hope to hear your Valentine's day stories, the best submissions will be published, email them at firstname.lastname@example.org
Have a great Valentine's day, and may the GMs grace let you get what you want out of Life. I'll be spending my Valentine's day well accompanied.