For the past several years I have started Writing Workshop by having the kids write in journals about something that really happened to them. We do small moment stories and talk about picking one part etc. I usually do this for a few months, then we do personal narratives with a beginning/middle/end and then move into other genres- research, poetry, letter writing and persuasive. My kids just LOVE the other genres and most are kind of blah about writing yet another story of something that happened to them. I think part of it is just that we spend so much time on this one genre.
I was thinking about starting the year with "Writer's Notebooks" instead of journals, and exposing the kids to different genres even at the beginning of the year. For example, when teaching labels, the kids could label a picture of something that happened to them, and then later that week label a picture of a pumpkin after we read a nonfiction books about pumpkins. Something like that.