If you're a bit of a perfectionist as I am, and after a "right" way of doing things, and don't particularly like js/css hacks, then you might want to consider the custom action approach:
<CommandUIDefinition Location="Ribbon.ListForm.Edit.Commit.Publish" />
This will effectively and completely remove the
Save button from the New form of your list.
To remove it both from New and Edit form, use
Location="CommandUI.Ribbon" instead of
To remove the whole tab, change CommandUIDefinition location like this (not tested, but should work):
<CommandUIDefinition Location="Ribbon.ListForm.Edit" />