There's been a surprising amount of horror comedies over the years, most of them bad... real bad. Student Bodies (1981) claimed to be the first horror comedy, but Abbot and Costello were doing it in the 1940's, and Young Frankenstein was released in '74. I think the calculations amount to approximately nine awful horror comedies for every good horror comedy released. Let's test our hypothesis.
I submit to you Young Frankenstein, an undeniably good horror comedy. Accordingly, we have nine bad ones: Love at First Bite, Saturday the 14th, Haunted Honeymoon, Transylvania 6-5000, Little Shop of Horrors (1986 version), Vamp, Student Bodies, Once Bitten, and National Lampoon's Class Reunion.
Next, I give you Shaun of the Dead, a good horror comedy. The nine crap horror comedies are as follows:Bordello of Blood, Scary Movie 2, Scary Movie 3 (I'm being generous not classifying the first one as bad), Elvira, Mistress of the Dark, My Best Friend is a Vampire, Dracula: Dead and Loving It, Repossessed, Club Dread, and Bride of Chucky.
Of course, I'm being completely facetious, because the 1:9 ratio could be used for basically any genre. But it was fun anyway!