I did have the dll unregistered but since applying the unofficial patch, I have re-registered it. The general opinion is that the patch does work and is the best option until an official fix becomes available from Microsoft. Typing 'wmf vulnerablity' into a search engine, produces lots of articles about the flaw. Reading a few of them should help everyone decide what is best for them.
New articles come out, others keep being updated. The one linked to below is worth a read in my opinion. Also, as I understand it, IE users only have to visit a web page with a malicious file in it for the malware to execute, so it's not only e-mail attachments that carry the threat (see the articles linked to in Science and Technology).