It's fairly important to me, but not an absolute deal breaker.
It depends really. I do prefer DFK, that is the way I want to kiss a girl, but I can live with just FK as long as there is decent enthusiastic sex and a good blowjob provided.
Ultimately I'm there for my sexual pleasure, I want a good fuck with a hot girl. If DFK facilitates that then great, it adds to the experience, if it doesn't then it's kind of pointless. I have had a few experiences with really good DFK where the actual sex has been disappointing.
No kissing at all though, or awkward tense kissing, well that's not my idea of fun.