The subscribe to feed cannot be removed. It can be hidden with CSS editing provided you have CSS editing skills, are prepared to pay for an annually renewable custom CSS upgrade and are prepared to do the work yourself.
For dropdowns
1. You create a custom menu. http://en.support.wordpress.com/menus/
2. You add the Parent pages you want to display and arrange them in the order you want.
3. Then you add and drop and drag the subpages below the appropriate Parent pages, and when you have everything arranged in the menu that you want you save the menu.
4. Go to the “theme location” module at upper left on the menu page. Select your custom menu name from the pulldown labeled “primary location.” Click the save button in that module.
5. Refresh your browser so that it isn’t possibly pulling a cached page, and view see your new menu with Parent pages and dropdowns to sub-pages.
Note: If you wish you can also include pages and sub-pages of your own choice and custom links in your custom menu as well.