I'm very glad you added that menu feature to your 3.0 wordpress.
But there are some features that could make it much more usable.
First. I'd really like to see custom classes for menu items.
Like if I was adding "special" class to highlight one of the items somehow.
Second. Make menu items that link to one level autopopulate its subitems. This can be (and must be) an option of course. And could be applied to both pages and categories.
Thank you for your attention!