[Nancy Fulda]

I think think real issue under discussion here is 'tension'.

Love and violence are two ways to introduce tension into a manuscript, but they are not the only ways, and in fact if used carelessly, they can begin to feel klunky instead of grabby.

Todd McCaffrey's literary agent, Donald Maass, advises authors to maintain tension on every page. I consider this to be excellent advice. The thing to remember here is that tension requires a reader to be both (a) emotionally invested in the characters and their wellbeing, and (b) uncertain about the outcome of the immediate situation.

This is why love triangles are so common. If a romance novel features only one guy and one girl, it's pretty obvious that they're going to end up together; the outcome is not in doubt, only the means by which we'll end up there. Introducing a second love interest automatically raises tension levels because now the reader is uncertain about which fellow the heroine will fall for.

Similarly, life-and-death jeapordy is often not as effective as authors might hope. You can put your protagonist's life in peril all you want, but chances are, if you're only 25% into the novel, that readers know he's not really going to die. It's often far more effective to threaten the protagonist's favorite pet, a treasured relationship, or something equally dear to him. Readers know that the protagonist isn't going to die. They're much less certain about whether he's going to lose his job/reputation/girlfriend/whatever.

Umm... so I think I've strayed off-topic here a bit. I guess my main point is I don't think it matters whether you pick love or violence. Far more important is how well you apply your chosen technique.