As a horror fan, you can't let your bloodlust slide just cuz it's a slushy, soppy, lovey-dovey holiday, amirite? There plenty for the Valentine's gorehound to enjoy...
1. Valentine (2001)
Valentine brings together a host of early 2000's youngsters - Marley Shelton, Katherine Heigl, Jessica Capshaw - and inventively slaughters them for your viewing delectation. The swift, merciless dispatch of an icily pitch-perfect Denise Richards with a hot tub and an electric drill is a glorious high point.
2. My Bloody Valentine (1981)
This movie has gotten more critical recognition of late. Notably, My Bloody Valentine made it into James Marriott & Kim Newman's Horror! 333 Films to Scare You to Death: a must for every horror fan's collection.
Also, here's the lovely, Gordon Lightfoot style folksy theme song! Sung by Paul Zaza and John McDermott, this is a real favorite of mine.
3. My Bloody Valentine 3D (2009)
OK, before anyone gets mad about there being two My Bloody Valentine movies in this post, let's focus on the fact that they are two entirely different films, as any horror fan would know. MBV 3D is a vividly bloodthirsty, hilarious and campy joy - where else do you get a fight between a masked killer and a chick wearing only high heels? A warning, though: it may put you off laundromats for life...
4. Lovers Lane (1999)
OK, the tagline 'There's no such thing as safe sex' has probably already warmed your heart to this late-90's, straight-to-video slashfest. Predictably, a group of kids - including a young Anna Faris - are stalked by a Valentine's-crazed lunatic in an enthusiastically 80's fashion. If you can find this near-forgotten VHS relic, it's totally worth a watch.
5. Be My Valentine...Or Else! (1982)
Alternative titles for this early-80's rarity include Hospital Massacre, Ward 13 and X-Ray, all of which are like gold dust for VHS-loving ebay-trawlers. Cult status aside, the actual movie is high in gore and low in plot - hardly a surprise for a seasonal horror! - following the stalking of a nurse by a humiliated ex-love interest.