When I was at Con*Cept two months ago, I was on a panel discussing urban fantasy, and I said something that I now realize wasn't really true. I told that audience that, when it comes to my writing, my first instinct is to go for something funny. I'd like to think that about myself - I like the image of me as a funny guy - but that doesn't accurately describe everything I write. As soon as I'd said it, hundreds of examples of my 'serious' side went through my mind.
For example, I have two as-yet-unpublished novels called The Last Nephilim and The Last Nephilim's Decision that aren't funny at all. They tell the story of a girl who discovers she is an angel/human hybrid (a nephilim), and that angels have been hunting her kind into extinction since the beginning of creation. In fact, she's the very last one. The books have elements of Buffy The Vampire Slayer and Star Wars in them, and I could have easily chosen to write them funny. I did not, however. I wanted them serious, and I wanted them dark. And, not to toot my own horn or anything, but The Last Nephilim came 3rd place in a literary contest.
Another example is Cupidity, one of the books I'm working on now. It's about a teen who dies and becomes a Cupid, responsible for making people fall in love with each other. I planned for it to be funny, but I think the mix will be more half-and-half when it is done. It won't be as funny as Epoch or Soul Hunters, but I'm happy with the way it is turning out. The thing is, that might make it a bit harder to market, since my previous books have established me as a funny guy with wacky stories. I love telling people that Epoch is a comedy about the end of the world, because that always gets people's attention. And people love to laugh. But will readers follow me if my next book is dark and creepy?
Is there a place for my more serious side? I'd like to hope so. Some writers manage that balance quite nicely; Tanya Huff and Peter David come to mind. Basically, I'm still developing my voice, and I write the way the story tells me it wants to be written. Hopefully I will find that balance that Tanya and Peter do so (seemingly) effortlessly. Until then, I'm thinking of shoe-horning some more jokes into Cupidity.