We have just learned that the upcoming BMW Z4 will have both options: soft and hardtop. The source is absolutely credible, so no reason to doubt that
I'm not sure if the moderator will remove the link, but here is the article
http://www.bmwblog.com/2008/04/10/yo...nd-a-soft-top/
Personally, I prefer the hardtop, but just because I live in the Midwest, so pretty much our winters last for 6 months