Writing Multiple Genres

When I began writing again in early 2010, I thought I knew the type of books I'd write. Paranormal/Urban Fantasy YA.  A year later, I still identify with those genres, but my current work is YA contemporary, and I have 20+ pages of world building for a dystopian novel and I also have an idea for an adult urban fantasy novel.  Now I'd classify myself as a writer of many genres.

When I started writing my contemporary novel, I found my process changed. I've always written quick, even when I was a pantser. Ideas come to me. Now that I outline ahead of time, the ideas still come to me (I often change things as I go) but I spend a lot more time crafting each chapter. I'm learning stuff about myself as a writer that I don't think I would have if I'd stayed inside my 'genre box'. That's not to say that writers that only write one particular genre aren't talented at what they do, but I have to say I really admire writers whose works span genres.

Do you write many genres? Why or why not?